Play is critical to children's development in social, cognitive, and affective domains Children actively construct meaning through playful interaction with people and objects Play materials and environments in turn, affect the level structure and content of children's play The following article discusses these issues and the application of contemporary architectural design and current research findings on play environments to the special problems of hospitalized children Concerns related to separation from family and routine unfamiliar hospital personnel and procedure institutionalization and temporary immobility can be constructively dealt with by thoughtful planning for childrens play Specific suggestions with respect to designing play spaces in hospitals are offered based on current theory and research.