U.S. intelligence officials in early postwar Czechoslovakia had access to some of the Czechoslovak government's highest-ranking individuals and plenty of time to prepare for the looming confrontation with the Czechoslovak Communist Party. Yet the Communist takeover in February 1948 took them by surprise and undermined their networks. This article discusses the activities of four Czechoslovak security and intelligence agencies to demonstrate that the scale of the U.S. failure in Prague in 1945–1948 was far greater than often assumed, especially if one considers the substandard size and quality of Czechoslovakia's Communist-dominated special services after the war.