The goal of the current study was to examine the contribution of three early social skills that may provide a foundation for cooperative performance in autism: (1) imitation, (2) joint attention, and (3) understanding of other people's intentions regarding actions on objects. Fourteen children with autistic disorder (AD) and 15 children with other developmental disabilities (DDs) matched on non-verbal developmental age (AD, mean 27.7, SD 9.8; DD, mean 33.4, SD 11.1) and verbal developmental age (AD, mean 21.5, SD 12.3; DD, mean 28.4, SD 11.0) participated in the study. Children with autism showed poorer performance on imitation and joint attention measures, but not on the intentionality task. Multiple regression analyses showed that imitation skills and joint attention contributed independently to cooperation, above and beyond the understanding of intentions of actions on objects. (Contains 5 tables.)