This paper reviews the current literature on the suggested uses of play for assessment, prevention, and intervention with special needs children. The paper also uses case studies to illustrate the ways play is being used to facilitate achievement of early intervention goals and discusses advantages and disadvantages of these uses of play. The play-based model of assessment involves observation of children's sensorimotor, symbolic, and social play by a transdisciplinary team. Parents are taught directive or playful techniques that minimize problems that arise from dysfunctional parent-child interaction patterns, and thus prevent developmental delays on the part of at-risk children. The use of play for educational intervention involves the development of play skills as a planned part of a curriculum and the incorporation of playful approaches for mastery of skills in other domains, such as language or social skills. This paper defines play and addresses questions about what constitutes play in play-based assessment, in parent-child social interaction, and in play intervention. Appendix 1 describes the three assessments used as examples in the text, and Appendix 2 presents additional examples of prevention and intervention through play. (BC)