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 AndrÃÂ©s Manuel LÃÂ³pez 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 CorazÃÂ³n por MÃÂ©xico 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 LÃÂ³pez, 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 FernÃÂ¡ndez NoroÃÂ±a is elected President of the Senate and Ifigenia MartÃÂnez y HernÃÂ¡ndez 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 86Ã¢ÂÂ41 vote at around 04:00 CST the following morning.
25 September 2024: The Senate voted 86Ã¢ÂÂ42 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 MartÃÂnez y HernÃÂ¡ndez dies.
8 October 2024: Sergio GutiÃÂ©rrez 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 86Ã¢ÂÂ39 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 343Ã¢ÂÂ129 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 LÃÂ³pez 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 432Ã¢ÂÂ28 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 GutiÃÂ©rrez Luna continues as President of the Chamber of Deputies.
2 September 2025: Kenia LÃÂ³pez RabadÃÂ¡n 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 74Ã¢ÂÂ22 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 97Ã¢ÂÂ19 vote.

Major legislation

Constitutional amendments

Budgets

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

Chamber of Deputies

Leadership

Senate Board

2024Ã¢ÂÂ2025

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 FernÃÂ¡ndez NoroÃÂ±a 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.

2025Ã¢ÂÂ2026

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.

Chamber of Deputies Board

2024Ã¢ÂÂ2025

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 MartÃÂnez y HernÃÂ¡ndez (Morena) was chosen as President of the Chamber of Deputies with 496 votes in favor.

On 5 October 2024, President MartÃÂnez y HernÃÂ¡ndez died, and First Vice President Sergio GutiÃÂ©rrez Luna was elected as substitute president on 8 October 2024 to finish her term. Dolores Padierna Luna was elected as First Vice President, taking GutiÃÂ©rrez Luna's place. On 1 April 2025, Vice President MarÃÂa del Carmen Pinete Vargas died, and MarÃÂa Luisa Mendoza MondragÃÂ³n was elected with 394 votes on 22 April 2025 to complete the term.

On 31 August 2025, following MorenaÃ¢ÂÂs rejection of the PANÃ¢ÂÂs proposals for the presidency of the Chamber for the second legislative year, the term of the 2024Ã¢ÂÂ2025 Board of Directors was extended until 5 September.

2025Ã¢ÂÂ2026

Parliamentary coordinators

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.

Aguascalientes

Juan Antonio MartÃÂn del Campo (PAN)

MarÃÂa de JesÃÂºs DÃÂaz Marmolejo (PAN)

Nora Ruvalcaba GÃÂ¡mez (MORENA)

Baja California

Julieta RamÃÂrez Padilla (MORENA)

Armando Ayala Robles (MORENA)

Gustavo SÃÂ¡nchez VÃÂ¡squez (PAN)

: (PAN)

Baja California Sur

LucÃÂa TrasviÃÂ±a Waldenrath (MORENA)

Homero Davis Castro (MORENA)