The role of the CIA in the Cuban Missile Crisis was of crucial importance to events and decisions. This article explores and evaluates the activities of the CIA in the crisis. It examines how intelligence-gathering and analysis were conducted and how assessments and information were provided to decision-makers. The study of the crisis illuminates many aspects of intelligence. On some of these there remain debates. The significance of CIA covert action against Cuba prior to October 1962, for example, is explored. Another important focus is the mistaken assessment of the US intelligence community that the Soviets were not going to deploy nuclear missiles in Cuba. The nature and significance of this conclusion is considered, along with the views of the Director of Central Intelligence, John McCone, who contrary to his analysts, believed Khrushchev would deploy nuclear missiles. The view that the CIA played a successful part in monitoring the Soviet military build-up after the discovery of medium-range ballistic missiles is analysed. The lack of success in identifying Soviet tactical nuclear weapons is also considered. The article draws upon an extensive corpus of scholarship on the crisis, as well as declassified material and reflections of former officials. Research into the crisis extends to Soviet and other decision-makers and thus helps facilitate a more genuinely international intelligence history of the Cold War. The article proffers a reflective and nuanced assessment that underlines the achievements as well as the shortcomings of the CIA at this most crucial moment in the Cold War.