Destination countries have been resorting to selective immigration policies to improve migrants' quality. We propose a model that analyzes the effects of selective immigration policies on migrants' quality, measured by their wages at destination. Screening potential migrants on the basis of observable characteristics also influences their self-selection on unobservables that influences their wages. We show that the prevailing pattern of selection on unobservables influences the effect of an increase in selectivity, which can reduce migrants' quality when migrants are positively self-selected.