This article analyzes the AFL-CIO’s anticommunist international policy in the period just before and after the overthrow of democratic regimes in Brazil (1964) and Argentina (1966–1976). It focuses on the activities of the American Institute for Free Labor Development (AIFLD), a labor organization closely associated with US foreign policy interests. By highlighting similarities, differences, and direct connections between US labor activities in these two South American countries, I argue that Brazil’s 1964 coup and subsequent dictatorship were key experiences for US trade unionists as they formulated an AFL-CIO labor policy for Argentina and the rest of the Southern Cone.