Abstract Children with autism spectrum disorders (ASDs) often present with challenging behavior, such as aggression and self-injury. In studies of children with other types of developmental disabilities challenging behavior appears more often to be maintained by attention or escape from demands. Less is known about the operant function of challenging behavior in children with ASD. The aim of the present study was to provide an analysis of the function of challenging behaviors in 10 children with ASD or PDD-NOS. Each child was assessed across five conditions (i.e., attention, escape, tangible, alone, and play). Each condition was presented 8–10 times in a multielement design while the percentage of 10-s intervals with challenging behavior (e.g., aggression, self-injury) was recorded. The results showed that for 8 of the 10 children, challenging behavior was maintained by automatic reinforcement, but by multiple sources of reinforcement for the other 2 children. The overall findings differ from the results of studies on children with other types of developmental disabilities, suggesting the possibility of a characteristically more non-social function to the challenging behavior of children with ASD.