Understanding Argentina’s 2025 midterm elections – a guide

Midterm elections are held in Argentina every two years and with them half the Chamber of Deputies and a third of the Senate are renewed. Even though the implication of these polls is legislative, they are usually construed as the most reliable indication as to the approval or disapproval of an administration, acting almost as a referendum on the President’s time in office to date.

Nationwide representatives will be defined tomorrow, but in the 14 provinces which did not split their elections, provincial and municipal legislators will also be elected, in addition to the case of Santiago del Estero, which will also elect a governor.

On this occasion, 127 lawmakers will be renewed in the Lower House, as well as 24 in the Upper House. All provinces are electing deputies, but not senators, which will only be renewed in Salta, Chaco, Santiago del Estero, Entre Ríos, Neuquén, Ríos Negro, Tierra del Fuego & Islas del Atlántico Sur and Buenos Aires City.

Argentina’s lower house Chamber of Deputies comprises 257 members and the Senate consists of 72. In each of them, the seats of legislators expire after terms of four and six years respectively. 

An interesting note – after the return to democracy from dictatorship in 1983, all members had to be elected so that they all acquired the same seniority, and thus, to determine which ones had to leave their post after two, four or six years to complete a constitutional term, lots were drawn,

As for representation in Congress, senators are divided into three per province while the distribution of deputies is determined by the population of each jurisdiction. There are those who argue that the number of deputies must be updated since, for example, Buenos Aires Province may be underrepresented even if it is the one with the largest number of seats.

Parties

Considering the results of the 2021 election, Peronism, presented as Fuerza Patria, is the caucus with the most deputies and senators at stake, since it is renewing 47 seats in the lower house and 14 in the upper chamber. 

La Libertad Avanza, on the other hand, is risking little, as in the last midterm election it did not put up candidates in every constituency and only 10 of its lower house seats (including recruits from PRO) are expiring.

PRO, which in several jurisdictions – such as Buenos Aires Province, Buenos Aires City and Mendoza, among others – has sealed an alliance with the libertarians and has accompanied nearly all the ruling party’s initiatives, is renewing 19 deputies and three senators. 

Elsewhere, the Unión Cívica Radical are re-electing 10 deputies for their UCR caucus and nine for the Democracia para Siempre splinter. In the Senate, the century-old party has four representatives departing. Encuentro Federal is renewing seven seats.

In terms of the distribution of legislators for every political force, the breakdown of senators is simple: two for the majority and one for the first minority, that is, the runners-up. 

On the other hand, for the Chamber of Deputies, the D’Hondt method is used starting from an electoral floor of three percent of the constituency’s roll (Article 160, National Electoral Code, Law 19,945). 

The D’Hondt method implies that “the votes of every ticket are divided successively by 1, 2, 3, etc., allocating seats based on the highest quotients until the total disputed in every constituency is filled,” according to the Latin American Strategic Geopolitics Centre (CELAG).

Since the return to democracy, the electoral system has been amended. On the one hand, in 1991 the 30-percent quota of female representation in tickets was first introduced (Law 24,012). That percentage was expanded to a mandatory 50 percent with the Gender Parity Law in 2017 (Law 27,412). 

This year, the Single Paper Ballot will be used in the whole country for the first time.

Renewal of deputies and senators by province

– Buenos Aires Province: renewal of 35 seats in the Chamber of Deputies, 15 of Unión por la Patria (UxP), seven of PRO, three of Coalición Cívica (CC), three of Encuentro Federal, two of La Libertad Avanza (LLA), two of Democracia para Siempre, one of UCR, one of PTS-Frente De Izquierda Unidad, one of Izquierda Socialista FIT-Unidad.
– Jujuy: renewing three seats in the Chamber of Deputies, one of Unión por la Patria (UxP), one of UCR, one of PTS-Frente de Izquierda Unidad.
– Salta: renewing three seats in the Senate, two of Unidad Ciudadana, one of Cambio Federal; and three seats in the Chamber of Deputies, one of Innovación Federal, one of UxP, one of LLA.
– Formosa: renewing two seats in the Chamber of Deputies, one of UxP, one of Democracia para Siempre.
– Chaco: renewing three seats in the Senate, two of Frente Nacional y Popular, one of Unión Cívica Radical. In the Chamber of Deputies it is renewing four seats, two of UxP, one of Democracia para Siempre, one of PRO.
– Catamarca: renewing three seats in the Chamber of Deputies, two of UxP, one of UCR.
– Tucumán: renewing four seats in the Chamber of Deputies, two of Independencia, one of Creo, one of UCR.
– Santiago del Estero: renewing three seats in the Senate, all three for Frente Nacional y Popular. In the Chamber of Deputies it is renewing three seats, all of them UxP.
– La Rioja: renewing two seats in the Chamber of Deputies, both UxP.
– Córdoba: renewing nine seats in the Chamber of Deputies, three of UCR, three of Encuentro Federal, two of PRO, one of UxP.
– Santa Fe: renewing nine seats in the Chamber of Deputies, three of PRO, two of UxP, one of Unidos, one of Encuentro Federal, one of Democracia para Siempre, one of Defendamos Santa Fe.
– Misiones: renewing three seats in the Chamber of Deputies, one of UCR, one of Innovación Federal, one of LLA.
– Corrientes: renewing three seats in the Chamber of Deputies, one of Democracia para Siempre, one of PRO, one of UxP.
– Entre Ríos: renewing three seats in the Senate, one of Frente Pro, one of Unión Cívica Radical, one of Unidad Ciudadana. In the Chamber of Deputies it is renewing five seats, two of UxP, one of Democracia para Siempre, one of PRO, one of UCR
– San Juan: renewing three seats in the Chamber of Deputies, two of UxP, one of Producción y Trabajo.
– Mendoza: renewing five seats in the Chamber of Deputies, two of UxP, two of UCR, one of LLA.
– San Luis: renewing three seats in the Chamber of Deputies, one of LLA, one of PRO, one of UxP.
– La Pampa: renewing three seats in the Chamber of Deputies, one of UxP, one of PRO, one of Democracia para Siempre.
– Buenos Aires City: renewing three seats in the Senate, one of Unión Cívica Radical, one of Frente Nacional y Popular, one of Frente Pro. In the Chamber of Deputies it is renewing 13 seats, three of PRO, three of UxP, two of LLA, one of Partido Obrero-Frente de Izquierda y de Trabajadores-Unidad, one of Democracia para Siempre, one of Encuentro Federal, one of Coalición Cívica, one of UCR.
– Neuquén: renewing three seats in the Senate, one of Movimiento Popular Neuquino, two of Unidad Ciudadana. In the Chamber of Deputies it is renewing three seats, one of UxP, one of UCR, one of MPN.
– Río Negro: renewing three seats in the Senate, two of Unidad Ciudadana,one of Juntos Somos Río Negro. In the Chamber of Deputies it is renewing two seats,one of Innovación Federal, one of PRO.
– Chubut: renewing two seats in the Chamber of Deputies, one of UxP, one of PRO.
– Santa Cruz: renewing three seats in the Chamber of Deputies, one of Por Santa Cruz, one of UxP, one of UCR.
– Tierra del Fuego & Islas del Atlántico Sur: renewing three seats in the Senate, one of Unión Cívica Radical, two of Unidad Ciudadana. In the Chamber of Deputies it is renewing two seats, one of UxP, one of Somos Fueguinos.

*It is worth noting that Fuerza Patria/Unión por la Patria in the Senate is divided into two caucuses: Unidad Ciudadana and Frente Nacional y Popular.