In contrast, the vote for the ruling Spanish Socialist Workers' Party (PSOE) fell to its lowest level up until that time, losing four of its previously 16 seats and remaining with 12.

United Left (IU) benefited from the Socialist defeat and entered the General Deputation for the first time with 2 seats, whereas the Riojan Party (PR)—which had formed the regional government together with the PSOE since 1990—obtained its best result since 1983.

[3] Voting for the General Deputation was on the basis of universal suffrage, which comprised all nationals over 18 years of age, registered in La Rioja and in full enjoyment of their political rights.

The 33 members of the General Deputation of La Rioja were elected using the D'Hondt method and a closed list proportional representation, with an electoral threshold of five percent of valid votes—which included blank ballots—being applied regionally.

[3][4][5][6] The General Deputation of La Rioja could not be dissolved before the date of expiry of parliament except in the event of an investiture process failing to elect a regional President within a two-month period from the first ballot.