How do maternal work conditions, such as psychological stress and physical hazards, affect children's development? Combining data from the Child Development Supplement of the Panel Study of Income Dynamics and the Occupational Information Network allows us to shed some light on this question. We employ various techniques including OLS with extensive controls, a value added approach and individual fixed effects in order to address potential endogeneity problems. Our results reveal that mothers' exposure to work-related hazards negatively affects children's cognitive development and to work-related stress negatively affects children's behavioral development. While maternal time investments play a small but significant role in mediating these negative associations, paternal time investments neither reinforce nor compensate these associations. (Contains 15 tables.)