The objective of this paper is to investigate the impact of the length of maternity leave on maternal health in a sample of working mothers. Two measures of depression and a measure of outpatient health visits are used to represent maternal health. Ordinary least squares models provide baseline estimates, and instrumental variables models account for the potential endogeneity of the return-to-work decision. The findings suggest that returning to work later is associated with a reduction in the number or frequency of depressive symptoms. There is suggestive but inconclusive evidence that longer maternity leave is associated with a lower probability of being a likely case of clinical depression and a lower likelihood of having frequent outpatient visits during the first six months after childbirth. These findings contribute to the literature on maternal leave policy, which focuses primarily on the benefits of leave for child health and development, by evaluating the influence of longer maternal leave on the health of mothers.