The effects of teaching mothers to imitate their young children during play sessions were studied with children (18 to 36 months old) who exhibited developmental delays in cognition, gross/fine motor skills, speech/language, self-help, and social skills. Mothers were taught to imitate, through providing a description of verbal and nonverbal imitation, demonstrating an imitation, providing practice in imitation, providing feedback on the amount of imitation, and graphing the number of imitations. The sessions occurred twice weekly in a center, and generalization data were collected in weekly home visits. A multiple probe design across six mother-child dyads was used to evaluate the imitation training. Results indicated that: mothers increased the frequency with which they imitated their children's behavior; they decreased the number of mands (a measure of directiveness) during intervention without specific programming regarding mands; the decrease in mands was maintained on 2-week follow-up measures; and a decrease in mands was found in the home environment for five of six mothers. The results for children indicate that during intervention they engaged in longer durations of toy play, engaged in shorter periods of watching their mothers play, and engaged in more unique play behaviors. (Contains 30 references.) (SW)