The organization was founded in 1824 as the Central American Congress (Spanish: Congreso Federal Centroamericano).

Until 2024, it was made up of 84 deputies, all of whom are elected by direct popular vote according to open-list proportional representation to serve three-year terms and are eligible for immediate re-election.

Of these, 64 were elected in 14 multi-seat constituencies, corresponding to the country's 14 departments, which return between 3 and 16 deputies each.

126, Constitution): On 1 June 2023, Salvadoran President Nayib Bukele issued a proposal to the Legislative Assembly to reduce the number of its seats from 84 to 60.

[4] El Salvador also returns 20 deputies to the supranational Central American Parliament, also elected according to open-list proportional representation from a single national constituency.