Because of the high rates of employment of mothers, a large and increasing number of preschool children receive regular care from someone else. This article develops and tests hypotheses about the choice of child care arrangements for younger and older preschool children, using data from the National Longitudinal Survey of Young Women. We argue that appropriate care depends on the age of the child. It includes care by the mother or a paid provider in the child’s home for children aged 0–2 and mother care and nursery school or center care for those 3–5. We estimate models of the mother’s employment and choice of child care separately for younger and older preschoolers. Our results show that need for care, presence of substitutes for the mother, financial resources, and preferences all affect both full-time care by the mother and the type of child care chosen by working women, although they affect these two decisions in different ways.