In 1955 he and Lloyd Free founded the Institute for International Social Research (IISR). The IISR was often asked by United States government agencies to conduct small-sample public opinion polls in foreign countries. Notably, Cantril and Free conducted a poll of Cuba during 1960 demonstrating great support for Fidel Castro, which was overlooked during the presidential transition between Eisenhower and Kennedy and read only after the Bay of Pigs Invasion fiasco.