This article explores US labor market changes that would take place as a result of an amnesty that would regularize the status of undocumented workers without changing the total size of the alien workforce. The theoretical analysis suggests that the influence of legal status on market wage rates and on minimum wage enforcement is weak and that to the extent that there is an effect, it depends on particular institutional arrangements. Although data are not adequate for a definite measurement of these effects, those data that are available support this conclusion. It appears that the presence of undocumented as opposed to resident aliens can weaken union organizing efforts.