This article reconstructs the intense cycle of workers' protest of the Summer of 1946 and its impact on the Chilean political system. Focusing on the Bulnes Square massacre and the national work stoppages of January 30 and February 4, it argues that the government established new repressive mechanisms to neutralize dissent, discipline the labor movement, and impose social peace after the end of World War II. To achieve this purpose, the article relies on primary sources rarely analyzed before, such as reports of the Trade Union and Confidential Section of the Investigations Police of Chile and the court record of the Bulnes Square massacre, in addition to hemerographic sources.