Women earned about 20.8% less than men in Mexico in 1987, a difference that increased to 22.0% by 1993. Using 1987-93 data from Mexico's National Urban Employment Survey, the authors study the role of occupational attainment in this wage differential. Most of the 1987-93 increase in the gender log monthly earnings gap, they find, can be explained by relative changes in human capital endowments; wage coefficient changes would have slightly reduced the gap, all else equal. The increasing male-female earnings differential was tempered by a substantial decline in gender differences in occupational attainment from 1987 to 1993. Most of the male-female differences in earnings in both 1987 and 1993 can be explained by differences in rewards to individual endowments rather than gender differences in endowments.