A study was conducted to examine the determinants of women's return to work following the birth of their first child among white, black, and Mexican-origin mothers. The study tested the hypothesis that the racial differentials evident in the 1960s and early 1970s relating to the employment of new mothers had disappeared with changes in the general pattern of female employment. Data on 449 black, 930 white, and 224 Mexican-origin women were drawn from the National Longitudinal Survey of Youth. The results indicated the expected pattern. Measures of a woman's human capital, such as value of time, job experience, and work role attitudes had similar effects in predicting postnatal return to work for all three groups. Other factors such as education, family income other than that earned by the woman, and residence in urban areas predicted return to work differently for black and white mothers. These results are linked to changes in job characteristics, the economy, and the family.