This paper presents an empirical analysis of immigrant participation in the welfare system using the 1970 and 1980 U.S. Censuses. The availability of two cross-sections allows for identification of cohort and assimilation effects. The data indicate that recent immigrant cohorts use the welfare system more intensively than earlier cohorts. In addition, the longer an immigrant household has been in the United States, the more likely it is to receive welfare. The analysis also suggests that a single factor, the changing national origin mix of the immigrant flow, accounts for much of the increase in welfare participation rates across successive immigrant waves.