Mario Angelo Procaccino (September 5, 1912 – December 20, 1995) was an Italian-American lawyer, comptroller, and candidate for Mayor of New York City.

In the early 1940s, Mayor Fiorello La Guardia heard him address a war-bond rally in Italian, and seeing how excited the crowd was, told him he should be in politics and arranged for an appointment to a $3,500-a-year post with the city's legal department.

Procaccino and O'Connor were elected, but Beame was defeated by the Republican and Liberal Party of New York joint nominee, John V. Lindsay, a member of the United States House of Representatives and a then ally of fellow New York liberal Republicans Governor Nelson A. Rockefeller and United States Senator Jacob K. Javits.

Procaccino narrowly carried the Bronx and Brooklyn, with Lindsay taking Manhattan and Queens, and Marchi took his native Staten Island.

As a result of Procaccino's slender plurality in the Democratic primary, the law was changed so that if no candidate carries at least 40 percent of the vote, a runoff election must be held.