It was called by Prime Minister Adolfo Suárez as part of the political reform of the Francoist regime, ongoing since shortly after Francisco Franco's death in 1975 and promoted by his successor, King Juan Carlos I.

Its aim was to elect a Constituent Cortes that was to draft a new constitution, which would ultimately lead to the repealing of the Fundamental Laws of the Realm and the culmination of the country's transition to democracy.

The Union of the Democratic Centre (UCD), the electoral coalition created to serve as Suárez's political platform in government, emerged as the largest party overall, albeit 11 seats short of an absolute majority.

The Communist Party of Spain (PCE), which had been the main opposition force to the dictatorship, and the right-wing People's Alliance (AP) of former Francoist minister Manuel Fraga, performed below expectations.

If the Senate rejected the bill as passed by Congress, discrepancies were to be submitted to a mixed commission and, if the deadlock persisted, a joint sitting of both chambers would convene as a single legislative body in order to resolve on the issue by an absolute majority.

[4][5] For the Congress of Deputies, 348 seats were elected using the D'Hondt method and a closed list proportional representation, with an electoral threshold of three percent of valid votes—which included blank ballots—being applied in each constituency.

As per the Succession Law of 1947, the Spanish monarchy was restored under the figure of Juan Carlos I, who quickly became the promoter of a peaceful democratic reform of state institutions.

[13] However, as incumbent Prime Minister Carlos Arias Navarro rejected any major transformation of the Spanish political system, rather supporting the preservation of Francoist laws, he was dismissed by the King in July 1976, who appointed Adolfo Suárez for the post.