# 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.
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 session 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.

## Major legislation
### Constitutional amendments

| DOF Citation | Official title | Votes | Votes | Published |
| DOF Citation | Official title | Deputies | Senate | Published |
| 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 |

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

### Chamber of Deputies

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

## Leadership
### Presiding officers
#### President of the Senate

| Session | Term | Portrait | Name | Party | Party |
| 1 | 1 September 2024 – Incumbent | | Gerardo Fernández Noroña | | National Regeneration Movement |

#### President of the Chamber of Deputies

| Session | Term | Portrait | Name | Party | Party |
| 1 | 1 September 2024 – 5 October 2024 | | Ifigenia Martínez y Hernández | | National Regeneration Movement |
| 1 | 8 October 2024 – Incumbent | | Sergio Gutiérrez Luna | | National Regeneration Movement |

### Parliamentary coordinators

| Party | Senate | Senate | Chamber of Deputies | Chamber of Deputies |
| National Action Party | Ricardo Anaya | since 2025 | Noemí Luna Ayala [es] | 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.