During Lázaro Cárdenas’s administration (1934-1940), public health policies were widely promoted, with special emphasis on the health of the working class. Thus, in 1937, the Department of Public Health and the Department of Labor worked closely organizing the First National Congress of Labor, Hygiene and Medicine, where work-related health issues were explored for the first time. The ailments of miners and metalworkers —revealing the high rates of the workers’ disability and the difficulty of the medicalization of their diseases— highlighted the shortcomings of the Federal Labor Law.