The use of a forced-contact procedure to increase the rate of interaction between a socially withdrawn 3 1/2-year-old boy and his peers is described in this paper. A play group, consisting of four 3- to 5-year-old children, met three times a week for approximately 45 minutes in the isolate child's home. Each session consisted of a structured activity, free play activities, and snack time. Peer interaction was forced by instructing the isolate child to pass out a choice of snacks to the other children and by requiring the child to ask each of these children which snack they would prefer. Measures of the child's participation behaviors were sampled during the 20-minute free play time. Results indicated that the procedure was effective in increasing the child's rate of participation with other children. A further increase in participation was achieved when the child's mother positively reinforced his active participation with the other children. (Author/JA)