This analysis extends the concept of role incompatibility to examine the potential incompatibilities between breastfeeding and maternal employment. I hypothesize that women may face both structural and attitudinal conflicts between these behaviors. To test this hypothesis, this analysis uses data from Cycle IV of the National Survey of Family Growth to examine the relationship between women's postpartum employment and breastfeeding behaviors in the U.S. from 1980 to 1986. Analyses find that significantly more women who are employed part-time are likely to breastfeed and for longer durations than women employed full-time, suggesting that conflicts between breastfeeding and working at a job vary by the intensity of the employment. Further, a discrete-time hazard model finds that women are more likely to stop breastfeeding in the month they enter employment, suggesting that these behaviors constrain each other. The policy implications of these constraints are examined.