The 1967 Survey of Economic Opportunity data are employed to test hypotheses about differences in migration selectivity depending on the structural distance traversed in the migration process. Theoretically, the greater the structural distance crossed in the migration process, the more rigorous would be the selectivity. Conversely, where migration involves movement between similar places, little selectivity would be expected. Structural distance was defined as movement across both regional and rural-urban axes. Selectivity was defined by the relative incidence of poverty among the various residence and migration categories. Analysis of movement into and out of the rural South revealed empirical relationships between variables consistent with the theory employed, although important exceptions were found. These exceptions required a modification of the theory.