This paper compares the effects of television viewing to the effects of imaginative play on children's cognitive development. The major developmental tasks which confront the growing child are presented and the significance of imaginative play as a critical feature of the child's cognitive and affective development is discussed. The cognitive properties of the television medium as they may affect the child developing in an environment in which TV is viewed three hours or more a day are then examined. Next, the relevant research relating play or reading as an active process and television as a more passive one are discussed. Finally, approaches to training parents to control children's viewing patterns more effectively and to use TV material to stimulate children's imaginative development are described. (Author/JMB)