Observed 16 autistic, 16 normal, and 16 Down syndrome children (age 3-6 years during separation and reunion with their mother in a laboratory playroom over three sessions. Children's responses to separation and reunion were assigned to one of five behavioral patterns that were weighted for intensity or level of response. No differences were found between groups in their behavioral responses during separation or reunion. Moreover, children in each group altered their responses according to the environmental setting which was varied over the three sessions. However, the autistic and Down syndrome groups did differ from the normal group in their consistency of behavioral patterns over the three observation sessions; both the former groups showed more individual variation in their separation and reunion patterns indicating that the expression of these patterns may be influenced by their associated developmental delay.