The Corts Valencianes were the devolved, unicameral legislature of the Valencian autonomous community, having legislative power in regional matters as defined by the Spanish Constitution and the Valencian Statute of Autonomy, as well as the ability to vote confidence in or withdraw it from a President of the Government. Voting for the Corts was on the basis of universal suffrage, which comprised all nationals over eighteen, registered in the Valencian Community and in full enjoyment of their political rights. The 89 members of the Corts Valencianes were elected using the D'Hondt method and a closed list proportional representation, with a threshold of 5 percent of valid votes—which included blank ballots—being applied regionally. Parties not reaching the threshold were not taken into consideration for seat distribution. Seats were allocated to constituencies, corresponding to the provinces of Alicante, Castellón and Valencia. Each constituency was entitled to an initial minimum of 20 seats, with the remaining 29 allocated among the constituencies in proportion to their populations on the condition that the seat to population ratio in any given province did not exceed three times that of any other. The electoral law provided that parties, federations, coalitions and groupings of electors were allowed to present lists of candidates. However, groupings of electors were required to secure the signature of at least 1 percent of the electors registered in the constituency for which they sought election. Electors were barred from signing for more than one list of candidates. Concurrently, parties and federations intending to enter in coalition to take part jointly at an election were required to inform the relevant Electoral Commission within ten days of the election being called.
Election date
The term of the Corts Valencianes expired four years after the date of their previous election. The election Decree was required to be issued no later than the twenty-fifth day prior to the date of expiry of parliament and published on the following day in the Official Journal of the Valencian Community, with election day taking place between the fifty-fourth and the sixtieth day from publication. The previous election was held on 8 May 1983, which meant that the legislature's term would have expired on 8 May 1987. The election Decree was required to be published no later than 14 April 1987, with the election taking place no later than the sixtieth day from publication, setting the latest possible election date for the Corts on Saturday, 13 June 1987. The Corts Valencianes could not be dissolved before the date of expiry of parliament.
Opinion polls
The table below lists voting intention estimates in reverse chronological order, showing the most recent first and using the dates when the survey fieldwork was done, as opposed to the date of publication. Where the fieldwork dates are unknown, the date of publication is given instead. The highest percentage figure in each polling survey is displayed with its background shaded in the leading party's colour. If a tie ensues, this is applied to the figures with the highest percentages. The "Lead" column on the right shows the percentage-point difference between the parties with the highest percentages in a given poll. When available, seat projections are also displayed below the voting estimates in a smaller font. 45 seats were required for an absolute majority in the Corts Valencianes.
