Coupled with justifications of nondescriptive and intuitive levels, research from Piaget's developmental theory is used to support play as a viable part of a day care curriculum. Within the context of Piaget's theory of play, three developmental stages or classifications of play are distinguished: (1) sensorimotor practice play (infants); (2) symbolic play (2 to 7 or 8 years of age); and (3) play activities with rules (7 to 11 or 12 years of age). A fourth level of play, constructive and creative play, which is neither successive nor hierarchical, is discussed within Piaget's schema as a "trasitional level." The advantages of using a rationale for play taken from developmental theory are listed; however, more research in this area is encouraged. (ED)