Women's labor force participation has increased sharply over the last two decades, particularly for married women with young children. This suggests women are spending less time out of the labor force for child bearing and rearing. Using the detailed information available in the NLSY, I explore women s decisions to return to work within one year of their first child's birth, focusing on the effect of child care costs. Consistent with economic theory, women facing lower child care costs are more likely to return to work as are women with higher potential wages and lower family income from other sources. (JEL J0)