Aggregate analyses of sexual inequality fail to explore directly the resources of structurally induced earnings differences. These differences may derive from between- and/or within-employer differences in the reward-attainment processes of working men and women. This paper examines the second of these two issues, i.e., within-employer sex differences in salary for the same job. Two hypotheses are considered: the so-called wage discrimination hypothesis refers to inequality generated by male-female differences in the direct rates of return to productive resources and hierarchical rank; the rank segregation hypothesis refers to inequality generated by denying women equal access to the higher-paying ranks to which a particular job ladder leads. Our results suggest that sex differences in salary attainment result more from rank segregation than from wage discrimination per se. The implications for the problem of sexual discrimination and the generalizability of the findings are discussed.