LXVI Legislature of the Mexican Congress

The LXVI Legislature of the Congress of the Union (66th Congress) is the current session of the legislative branch of Mexico, composed of the Chamber of Deputies and the Senate of the Republic. It convened on 1 September 2024, and will end on 31 August 2027, covering the final month of Andrés Manuel López Obrador's term in office and the first three years of Claudia Sheinbaum's presidency.

66th Congress
(LXVI Legislatura)
65th 67th
Legislative Palace of San Lázaro
Overview
Legislative bodyCongress of the Union
Term1 September 2024 (2024-09-01) – 31 August 2027 (2027-08-31)
Election2 June 2024
Senate
Members128 senators
President
  • Gerardo Fernández Noroña
    (1 September 2024 – 31 August 2025)
  • Laura Itzel Castillo
    (1 September 2025 – present)
Chamber of Deputies
Members500 deputies
President
  • Ifigenia Martínez y Hernández
    (1 September – 5 October 2024)
  • Sergio Gutiérrez Luna
    (8 October 2024 – 2 September 2025)
  • Kenia López Rabadán
    (2 September 2025 – present)

Both chambers of Congress were elected in the 2024 general election. There were three competing forces: the Sigamos Haciendo Historia coalition, consisting of the National Regeneration Movement (Morena), the Labor Party (PT), and the Ecologist Green Party of Mexico (PVEM); the Fuerza y Corazón por México coalition, comprising the National Action Party (PAN), the Institutional Revolutionary Party (PRI), and the Party of the Democratic Revolution (PRD); and the Citizens' Movement (MC), the only party to run without allies.

Sigamos Haciendo Historia won a supermajority in the Chamber of Deputies, granting the ruling coalition 73% of the seats, the highest share since the LII Legislature in 1982, during Miguel de la Madrid's presidency. Although the coalition fell three seats short of a supermajority in the Senate, defections by two senators elected for the PRD on 28 August closed the gap to one. The supermajority was ultimately secured with the defection to Morena of Cynthia López, elected for the PRI in Mexico City, on 12 November. This marked the first time since the LIII Legislature in 1985 that the ruling coalition held a supermajority in both chambers.

Major events

  • 29 August 2024: Members-elect are sworn in. Gerardo Fernández Noroña is elected President of the Senate and Ifigenia Martínez y Hernández is elected President of the Chamber of Deputies for the first year of the legislature.
  • 1 September 2024: Legislature convenes.
  • 10 September 2024: Protesters opposing the judicial reform bill storm the Senate building, temporarily halting the session discussing the reforms. The Senate reconvenes in its former premises and passes the bill by an 86–41 vote at around 04:00 CST the following morning.
  • 25 September 2024: The Senate voted 86–42 on a constitutional amendment that transfers the control of the National Guard to the Secretariat of National Defense.
  • 1 October 2024: Claudia Sheinbaum becomes President of Mexico.
  • 5 October 2024: President of the Chamber of Deputies Ifigenia Martínez y Hernández dies.
  • 8 October 2024: Sergio Gutiérrez Luna is elected President of the Chamber of Deputies.
  • 9 October 2024: The Senate unanimously approves a constitutional amendment aimed at ensuring that the minimum wage increases above inflation.
  • 16 October 2024: The Senate unanimously approves a constitutional amendment that enables the State to reclaim the right to provide passenger train transportation.
  • 16 October 2024: The Senate voted 86–39 on an energy reform bill that reestablishes the Federal Electricity Commission (CFE) and Pemex as public entities and mandates that the CFE retains a 54% share of electricity generation.
  • 30 October 2024: The Chamber of Deputies voted 343–129 on a constitutional amendment that enshrines constitutional supremacy, allowing legal challenges to constitutional amendments only on procedural grounds.
  • 12 November 2024: Morena and its allies secure a supermajority in the Senate with the defection of Cynthia López Castro.
  • 12 February 2025: The Senate submitted the final list of candidates for the 2025 Mexican judicial elections to the National Electoral Institute (INE).
  • 4 March 2025: The Chamber of Deputies voted 432–28 on a bill banning immediate reelection and prohibiting family members of current officeholders from seeking the same elected position. The reform is scheduled to take effect in 2030.
  • 29 August 2025: Laura Itzel Castillo is elected President of the Senate for the second year of the legislature.
  • 31 August 2025: The Chamber of Deputies postpones the renewal of its Board of Directors until 5 September amid Morena's rejection of PAN proposals; Sergio Gutiérrez Luna continues as President of the Chamber of Deputies.
  • 2 September 2025: Kenia López Rabadán is elected President of the Chamber of Deputies for the second year of the legislature.
  • 27 November 2025: The Senate approves the resignation of Attorney General Alejandro Gertz Manero in a 74–22 vote.
  • 3 December 2025: The Senate compiled a list of ten finalists for the position of Attorney General, which the President narrowed to a shortlist of three. After the three finalists testified before the chamber, the Senate appointed Ernestina Godoy Ramos as Attorney General in a 97–19 vote.

Major legislation

Constitutional amendments

DOF Citation Official title Votes Published
Deputies Senate
15-09-2024 A decree to amend, add, and repeal various provisions of the Political Constitution of the United Mexican States, regarding the reform of the Judicial Branch

Decreto por el que se reforman, adicionan y derogan diversas disposiciones de la Constitución Política de los Estados Unidos Mexicanos, en materia de reforma del Poder Judicial

4 September 2024
(357–130)
11 September 2024
(86–41)
15 September 2024
30-09-2024 A decree to amend, add, and repeal various provisions of the Political Constitution of the United Mexican States, regarding Indigenous and Afro-Mexican Peoples and Communities

Decreto por el que se reforman, adicionan y derogan diversas disposiciones del artículo 2o. de la Constitución Política de los Estados Unidos Mexicanos, en materia de Pueblos y Comunidades Indígenas y Afromexicanos

18 September 2024
(483–0)
24 September 2024
(128–0)
30 September 2024
30-09-2024 A decree to amend and add Articles 13, 16, 21, 32, 55, 73, 76, 78, 82, 89, 123, and 129 of the Political Constitution of the United Mexican States, regarding the National Guard

Decreto por el que se reforman y adicionan los artículos 13, 16, 21, 32, 55, 73, 76, 78, 82, 89, 123 y 129 de la Constitución Política de los Estados Unidos Mexicanos, en materia de Guardia Nacional

19 September 2024
(353–126)
24 September 2024
(86–42)
30 September 2024
30-10-2024 A decree to amend the fourth paragraph and add a fifth paragraph to Article 28 of the Political Constitution of the United Mexican States, regarding railways and railway transportation

Decreto por el que se reforma el párrafo cuarto y se adiciona un párrafo quinto al artículo 28 de la Constitución Política de los Estados Unidos Mexicanos, en materia de vías y transporte ferroviario

8 October 2024
(472–0)
16 October 2024
(123–0)
30 October 2024
31-10-2024 A decree to amend the fifth paragraph of Article 25, the sixth and seventh paragraphs of Article 27, and the fourth paragraph of Article 28 of the Political Constitution of the United Mexican States, regarding strategic areas and enterprises

Decreto por el que se reforman el párrafo quinto del artículo 25, los párrafos sexto y séptimo del artículo 27 y el párrafo cuarto del artículo 28 de la Constitución Política de los Estados Unidos Mexicanos, en materia de áreas y empresas estratégicas

9 October 2024
(350–111)
16 October 2024
(86–39)
31 October 2024
31-10-2024 A decree to amend the first paragraph of Section II of Article 107 and add a fifth paragraph to Article 105 of the Political Constitution of the United Mexican States, regarding the unchallengeability of additions or amendments to the Federal Constitution

Decreto por el que se reforma el primer párrafo de la fracción II del artículo 107, y se adiciona un quinto párrafo al artículo 105, de la Constitución Política de los Estados Unidos Mexicanos, en materia de inimpugnabilidad de las adiciones o reformas a la Constitución Federal

30 October 2024
(343–129)
24 October 2024
(85–41)
31 October 2024
15-11-2024 A decree to amend and add Articles 4, 21, 41, 73, 116, 122, and 123 of the Political Constitution of the United Mexican States, regarding substantive equality, gender perspective, women's right to a life free of violence, and the elimination of the gender pay gap

Decreto por el que se reforman y adicionan los artículos 4o., 21, 41, 73, 116, 122 y 123 de la Constitución Política de los Estados Unidos Mexicanos, en materia de igualdad sustantiva, perspectiva de género, derecho de las mujeres a una vida libre de violencia y erradicación de la brecha salarial por razones de género

5 November 2024
(468–0)
24 October 2024
(126–0)
15 November 2024
02-12-2024 A decree to amend and add Articles 4 and 27 of the Political Constitution of the United Mexican States, regarding well-being

Decreto por el que se reforman y adicionan los artículos 4o. y 27 de la Constitución Política de los Estados Unidos Mexicanos, en materia de bienestar

22 October 2024
(408–65)
30 October 2024
(117–0)
2 December 2024
02-12-2024 A decree to amend and add Section XII of Subsection A of Article 123 of the Political Constitution of the United Mexican States, regarding housing for workers

Decreto por el que se reforma y adiciona la fracción XII del Apartado A del artículo 123 de la Constitución Política de los Estados Unidos Mexicanos, en materia de vivienda para las personas trabajadoras

23 October 2024
(472–0)
31 October 2024
(103–0)
2 December 2024
02-12-2024 A decree to amend and add Articles 3, 4, and 73 of the Political Constitution of the United Mexican States, regarding animal protection and care

Decreto por el que se reforman y adicionan los artículos 3o, 4o y 73 de la Constitución Política de los Estados Unidos Mexicanos, en materia de protección y cuidado animal

12 November 2024
(441–0)
21 November 2024
(118–0)
2 December 2024
20-12-2024 A decree to amend, add, and repeal various provisions of the Political Constitution of the United Mexican States, regarding organizational simplification

Decreto por el que se reforman, adicionan y derogan diversas disposiciones de la Constitución Política de los Estados Unidos Mexicanos, en materia de simplificación orgánica

20 November 2024
(332–119)
28 November 2024
(86–40)
20 December 2024
31-12-2024 A decree to amend the second paragraph of Article 19 of the Political Constitution of the United Mexican States, regarding mandatory pretrial detention

Decreto por el que se reforma el párrafo segundo del artículo 19 de la Constitución Política de los Estados Unidos Mexicanos, en materia de prisión preventiva oficiosa

13 November 2024
(335–108)
27 November 2024
(93–35)
31 December 2024
31-12-2024 A decree to amend and add Article 21 of the Political Constitution of the United Mexican States, regarding public security

Decreto por el que se reforma y adiciona el artículo 21 de la Constitución Política de los Estados Unidos Mexicanos, en materia de seguridad pública

21 November 2024
(441–0)
13 November 2024
(122–0)
31 December 2024
17-01-2025 A decree to add a fifth paragraph to Article 4 and a second paragraph to Article 5 of the Political Constitution of the United Mexican States, regarding health protection

Decreto por el que se adicionan un párrafo quinto al artículo 4o y un párrafo segundo al artículo 5o, de la Constitución Política de los Estados Unidos Mexicanos, en materia de protección a la salud

3 December 2024
(327–118)
11 December 2024
(86–39)
17 January 2025
17-03-2025 A decree to amend and add various provisions of Articles 4 and 27 of the Political Constitution of the United Mexican States, regarding the conservation and protection of native maize.

Decreto por el que se reforman y adicionan diversas disposiciones de los artículos 4o. y 27 de la Constitución Política de los Estados Unidos Mexicanos, en materia de conservación y protección de los maíces nativos.

25 February 2025
(382–88)
5 March 2025
(88–18)
17 March 2025
01-04-2025 A decree to add a second paragraph to Article 123 of the Political Constitution of the United Mexican States, regarding support for youth

Decreto por el que se adiciona un segundo párrafo al artículo 123 de la Constitución Política de los Estados Unidos Mexicanos, en materia de apoyo a jóvenes.

25 September 2024
(473–0)
11 March 2025
(112–0)
1 April 2025
01-04-2025 A decree to amend and supplement Articles 55, 59, 82, 115, 116, and 122 of the Political Constitution of the United Mexican States, regarding non-reelection and electoral nepotism

Decreto por el que se reforman y adicionan los artículos 55, 59, 82, 115, 116 y 122 de la Constitución Política de los Estados Unidos Mexicanos, en materia de no reelección y nepotismo electoral.

4 March 2025
(432–28)
25 February 2025
(97–26)
1 April 2025
01-04-2025 A decree to amend the second paragraph of Article 19 and add second and third paragraphs to Article 40 of the Political Constitution of the United Mexican States, regarding the strengthening of national sovereignty

Decreto por el que se reforma el segundo párrafo del artículo 19 y se adicionan los párrafos segundo y tercero al artículo 40 de la Constitución Política de los Estados Unidos Mexicanos, en materia de fortalecimiento de la soberanía nacional.

11 March 2025
(327–116)
26 February 2025
(100–17)
1 April 2025
15-04-2025 A decree to amend the tenth paragraph of Article 25 and Subsection XXIX-Y of Article 73 of the Political Constitution of the United Mexican States, regarding administrative simplification and digitalization

Decreto por el que se reforman el párrafo décimo del artículo 25 y la fracción XXIX-Y del artículo 73 de la Constitución Política de los Estados Unidos Mexicanos, en materia de simplificación administrativa y digitalización.

19 March 2025
(425–19)
12 March 2025
(107–3)
15 April 2025

Budgets

Year Official title Votes Published Total expenditures
Deputies Senate
2025 Law of Revenues of the Federation for the Fiscal Year 2025

Ley de Ingresos de la Federación para el Ejercicio Fiscal de 2025

26 November 2024
(367–95)
4 December 2024
(84–36)
19 December 2024 MX$9.302 trillion
Budget of Expenditures of the Federation for the Fiscal Year 2025

Presupuesto de Egresos de la Federación para el Ejercicio Fiscal 2025

11 December 2024
(349–129)
24 December 2024
2026 Law of Revenues of the Federation for the Fiscal Year 2026

Ley de Ingresos de la Federación para el Ejercicio Fiscal de 2026

15 October 2025
(349–128)
29 October 2025
(80–37)
7 November 2025 MX$10.19 trillion
Budget of Expenditures of the Federation for the Fiscal Year 2026

Presupuesto de Egresos de la Federación para el Ejercicio Fiscal 2026

4 November 2025
(358–133)
21 November 2025

Party summary

These tables relate to the composition of the Senate of the Republic and the Chamber of Deputies at the start of the LXVI Legislature and their current makeup, highlighting the changes in party affiliation that have occurred during the legislature.

Senate

Party Start of
Legislature
Current
seats
±
National Regeneration Movement 66 67 1
National Action Party 22 21 1
Ecologist Green Party of Mexico 13 14 1
Institutional Revolutionary Party 15 13 2
Labor Party 6 6
Citizens' Movement 5 6 1
Independents / No party 1 1
Total 128 128

Chamber of Deputies

Party Start of
Legislature
Current
seats
±
National Regeneration Movement 257 253 4
National Action Party 71 70 1
Ecologist Green Party of Mexico 60 62 2
Labor Party 47 49 2
Institutional Revolutionary Party 36 37 1
Citizens' Movement 27 28 1
Independents / No party 1 1
Party of the Democratic Revolution 1 0 1
Total 500 500

Leadership

Senate Board

2024–2025

On 29 August 2024, the Senate elected the Board of Directors for the first year of the legislative period. In a secret ballot, Senator Gerardo Fernández Noroña of Morena was chosen as President of the Senate with 127 votes in favor. On 3 September, the Political Coordination Board approved an expansion of the Board of Directors for a one-year term, adding an additional vice presidency for the PVEM.

Post Name Term Party
President of the Senate Gerardo Fernández Noroña 1 September 2024

31 August 2025
National Regeneration Movement
First Vice President Imelda Castro Castro 1 September 2024

31 August 2025
National Regeneration Movement
Second Vice President Mauricio Vila Dosal 1 September 2024

31 August 2025
National Action Party
Third Vice President Karla Toledo Zamora 1 September 2024

31 August 2025
Institutional Revolutionary Party
Fourth Vice President Jorge Carlos Ramírez Marín 3 September 2024

31 August 2025
Ecologist Green Party of Mexico

2025–2026

On 29 August 2025, the Senate elected the Board of Directors for the second year of the legislative period. In a secret ballot, Senator Laura Itzel Castillo of Morena was chosen as President of the Senate with 101 votes in favor. The election marked the first time in 96 years that the Institutional Revolutionary Party (PRI) did not hold either the presidency or a vice presidency on the Board.

Post Name Term Party
President of the Senate Laura Itzel Castillo 1 September 2025

Incumbent
National Regeneration Movement
First Vice President Verónica Camino Farjat 1 September 2025

Incumbent
National Regeneration Movement
Second Vice President Imelda Sanmiguel Sánchez 1 September 2025

Incumbent
National Action Party
Third Vice President Jorge Carlos Ramírez Marín 1 September 2025

Incumbent
Ecologist Green Party of Mexico

Chamber of Deputies Board

2024–2025

On 29 August 2024, the Chamber of Deputies elected the Board of Directors for the first year of the legislative period. In a secret ballot, Ifigenia Martínez y Hernández (Morena) was chosen as President of the Chamber of Deputies with 496 votes in favor.

On 5 October 2024, President Martínez y Hernández died, and First Vice President Sergio Gutiérrez Luna was elected as substitute president on 8 October 2024 to finish her term. Dolores Padierna Luna was elected as First Vice President, taking Gutiérrez Luna's place. On 1 April 2025, Vice President María del Carmen Pinete Vargas died, and María Luisa Mendoza Mondragón was elected with 394 votes on 22 April 2025 to complete the term.

On 31 August 2025, following Morena’s rejection of the PAN’s proposals for the presidency of the Chamber for the second legislative year, the term of the 2024–2025 Board of Directors was extended until 5 September.

Post Name Term Party
President of the Chamber of Deputies Ifigenia Martínez y Hernández 1 September 2024

5 October 2024
National Regeneration Movement
Sergio Gutiérrez Luna 8 October 2024

2 September 2025
National Regeneration Movement
First Vice President Sergio Gutiérrez Luna 1 September 2024

8 October 2024
National Regeneration Movement
Dolores Padierna Luna 8 October 2024

2 September 2025
National Regeneration Movement
Second Vice President Kenia López Rabadán 1 September 2024

2 September 2025
National Action Party
Third Vice President María del Carmen Pinete Vargas 1 September 2024

1 April 2025
Ecologist Green Party of Mexico
María Luisa Mendoza Mondragón 22 April 2025

2 September 2025
Ecologist Green Party of Mexico

2025–2026

Post Name Term Party
President of the Chamber of Deputies Kenia López Rabadán 2 September 2025

Incumbent
National Action Party
First Vice President Sergio Gutiérrez Luna 2 September 2025

Incumbent
National Regeneration Movement
Second Vice President Paulina Rubio Fernández (es) 2 September 2025

Incumbent
National Action Party
Third Vice President Raúl Bolaños Cacho Cué 2 September 2025

Incumbent
Ecologist Green Party of Mexico

Parliamentary coordinators

Party Senate Chamber of Deputies
National Action Party Ricardo Anaya since 2025 Noemí Luna Ayala since 2024
Institutional Revolutionary Party Manuel Añorve Baños since 2024 Rubén Moreira Valdez since 2024
Labor Party Alberto Anaya since 2024 Reginaldo Sandoval Flores (es) since 2024
Ecologist Green Party of Mexico Manuel Velasco Coello since 2024 Carlos Alberto Puente Salas since 2024
Citizens' Movement Clemente Castañeda Hoeflich since 2024 Ivonne Ortega Pacheco since 2024
National Regeneration Movement Adán Augusto López since 2024 Ricardo Monreal since 2024


Senate members

Elected by state

In the list, the first two positions represent the senators from the winning two-name formula who secured a majority in the state. The third corresponds to the senator who earned a seat through first minority.

Elected by proportional representation

Chamber of Deputies members

Elected by district

Elected by proportional representation

See also

  • 2024 Mexican general election
  • 2024 Mexican Senate election
  • 2024 Mexican Chamber of Deputies election

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