The purpose of this study was to examine the effect of varying the number of consecutive trials on a pre-set criterion on the acquisition and retention of the overhand throw for children with mental retardation. Additionally, the study examined the differences between the mentally retarded and the nondisabled on acquisition and retention of the throw. Ninety-two participants (46 individuals with mental retardation, 46 nondisabled persons) were assigned to one of four groups. Participants were seen during the acquisition period until they completed the required number of throws. Retention testing took place three weeks following completion of the acquisition period. Result indicated that the nondisabled were able to acquire and retain the overhand throw with significantly fewer trials then the mentally retarded. However, significant differences did not exist between the initial amounts of overlearning and retention of the overhand throw