This article analyzes the role of pickets in two of the most emblematic strikes in Brazilian labor history during the twentieth century: the “strike of the 400,000,” which involved several industry categories in São Paulo and neighboring cities in 1957, and the “forty-one days strike” in 1980 involving the metalworkers of the industrial belt, known as ABC Paulista, in the metropolitan region of the city of São Paulo. Both strikes broke out at a time of profound reconfiguration of Brazilian society, marked by industrialization, migration, and urbanization processes. Although separated by a time gap of almost twenty-five years, both the “strike of the 400,000” and the “forty-one days strike” reveal important aspects of the performance of workers in that crucial period of Brazilian history.