The labor market effects of Mexican repatriations: Longitudinal evidence from the 1930s

•We examine the consequences on US workers of a significant return-migration episode during which at least 400,000 Mexicans returned to Mexico, between 1929 and 1934.•We instrument county level drop in Mexican population with the size of the Mexican communities in 1910 and its interaction with proxies of repatriation costs.•Using individual linked data on natives in the 1930 and 1940 Censuses, we find that Mexican repatriations resulted in reduced employment and occupational downgrading of native workers.•These patterns were stronger for low skilled workers and for workers in urban locations.•These patterns are consistent with Mexican workers being crucial for local agglomeration economies, and for attracting unskilled-intensive industries.