This article examines the effects of undocumented Mexican immigrants on the earnings of other workers in geographical labor markets in the Southwest. The number of undocumented Mexicans included in the 1980 census in southwestern SMSAs is estimated. We then estimate the parameters of three specifications of a generalized Leontief production function with various demographic groups as substitutable factors. The statistically significant effects of undocumented Mexicans on the earnings of other groups are positive, but of slight magnitude. Legal immigrants' effects on native white earnings, however, are small and negative. The results are consistent with the possibility that undocumented Mexican immigrants' jobs complement those of other workers. The implications for public policy concerns about the effects of illegal Mexican immigration are discussed.
Bean et al. (1988) studied this question.