More mothers than ever are now entering the work force and leaving greater numbers of preschool children and infants with less maternal supervision. How this phenomenon affects the development of infants and preschoolers has been the focus of much research, and research results have been mixed. A review of the research related to maternal employment and child development, while often contradictory, shows that the predicted catastrophic consequences of maternal employment and nonmaternal care are not strongly supported by existing data. The general results of studies relevant to the effects of maternal employment on parenting suggest that work status per se is not as important a factor as the attitudes of the mother and her family towards her employment status. Research exploring the attachment process suggests that high-quality day care centers seldom produce negative effects on attachment. Finally, the results of the effects of maternal employment on the child's emotional and cognitive development have generally found day care children to have either more peer orientation or no differences in peer orientation when compared to home-reared children. While these findings suggest that maternal employment may not adversely affect young children, research limitations, conflicting results, and the long-range predictions of theorists who support the importance of early maternal care must be considered. There is a need for quality longitudinal studies to examine the long-term effects of maternal employment on child development. A six-page reference list concludes the paper. (NB)