Receiving the endorsement of the exiled populist leader, Juan Perón four days before the February 1958 general elections, UCRI presidential candidate Arturo Frondizi defeated the more conservative People's UCR by 17% and the party enjoyed a narrow majority in Congress.

A proposed Popular Front uniting banned Peronists, the UCRI and others dissolved ahead of the July 1963 general elections, when Buenos Aires Province Governor Oscar Alende developed objections to the inclusion of conservatives in the alliance.

Frondizi, others in the UCRI and Perón instructed their supporters to cast blank ballots, leading to their highest incidence in the history of Argentine national elections.

Governor Alende ran on the Intransigent Party, but was unable to overcome the boycott, leading him to narrowly lose to People's UCR candidate Arturo Illia, a centrist.

Frondizi and his chief economist while in office, Rogelio Julio Frigerio, left the UCRI in August to establish the Integration and Development Movement (MID), whose platform centered on economic growth.