This study examined the effects of adult imitation and adult playfulness on the imitation, social attention and initiation of new behaviours by non-verbal preschoolers with autism. Videotapes taken from a previous study were recoded for the adult's imitation and playful behaviour and the children's imitation, social attention (looking at the adult's actions) and initiation of new behaviours. In the original study, twenty non-verbal, 4- to 6-year-old children with autism were randomly assigned to an imitation or a contingent responsivity group. Both groups of children engaged in an intervention phase (during which the adult imitated the children or contingently responded to them) and a subsequent spontaneous play phase (during which the adult interacted spontaneously with the children). ANOVA for the current study revealed that the imitation group children versus the contingent responsivity group children spent a greater percent time showing social attention and initiating new behaviours during the intervention phase and showing social attention and imitating the adult's behaviours during the subsequent spontaneous play phase. A correlation analysis yielded significant correlations between the percent time the adult imitated the child during the intervention phase and the percent time the child showed social attention during the same intervention phase and imitating the adult during the subsequent spontaneous play phase. Adult imitation and playfulness during the spontaneous play phase were also correlated with the children's social attention during that phase.