[1] The party came out first by winning the most votes and seats, but lost its absolute majority and suffered an important loss of support compared to its 1983 result.

[5] The PRP and two former CDS deputies would go on to join a PSOE motion of no confidence against Espert, resulting in Socialist José Ignacio Pérez Sáenz becoming new regional president in January 1990 of a PSOE–PRP government.

[6] The General Deputation of La Rioja was the devolved, unicameral legislature of the autonomous community of La Rioja, having legislative power in regional matters as defined by the Spanish Constitution and the Riojan Statute of Autonomy, as well as the ability to vote confidence in or withdraw it from a regional president.

[7] 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.

[7][8][9] 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.

The highest percentage figure in each polling survey is displayed with its background shaded in the leading party's colour.

[3] The minority government resulting from the AP–PRP agreement with the abstention from the CDS was forced into a precarious position which remained for its entire duration.