The study compared the results of group and individual training methods on the acquisition of a roll-on-deodorant self care skill by 16 profoundly retarded adults residing at a residential institution for the mentally retarded. The deodorant skill was divided into 11 teaching steps and an initial performance baseline was obtained for each subject. Ss were randomly assigned to either an individual or group treatment condition. In the group condition, one trainee with an assistant spent 30 minutes per day for 20 sessions with a group of four Ss. Each trainer also spent 20 minutes per day for 20 sessions teaching the same skill individually with four Ss. A performance baseline was obtained after every five sessions. The method of training was identical in the two conditions. The trainers used backward chaining; gave verbal, gestural, and physical prompts; and provided social and edible reinforcement. The assistant in the group condition helped maintain order and encouraged Ss to imitate the skill being taught. The data were analyzed in terms of effectiveness (i.e. did the Ss learn more in either the small group or individual training conditions?) and efficiency (i.e. did either the small group or individual training produce more learning per unit of teacher time?). The analysis of effectiveness revealed a higher, but statistically nonsignificant, average-step-learned measure for the group condition. However, when data were analyzed in terms of steps learned per hour of staff time, the group condition was significantly more efficient. (Author/SW)