Physical Activity levels found in adolescents with mental retardation (MR) are of considerable concern. A lack of opportunity for participation may lead to the failure of many individuals with MR to remain active outside of school-based programs. This would explain low fitness and accompanying higher incidence of cardiovascular disease in this population (Pitetti & Campbell, 1991). Related to this are motivation for physical activity and specifically self-determined behavior in persons with MR (Wehmeyer, 1994). An additional factor is caregiver physical activity. The purpose of this study is to explore physical activity and intrinsic motivation in seven individuals (ages 13–25) with MR. Participants were interviewed using The Pictorial Motivation Scale (TPMS) (Reid, Vallerand, & Poulin, 2001) and assessed using The Brockport Physical Fitness Test (Winnick & Short, 1999) to determine levels of motivation and fitness. Following assessment, each participant and their caregiver wore RT3 activity monitors over a seven-day period. The RT3s are motion sensitive devises that record movement in participants during waking hours and calculate a composite variable of vector magnitude (movement in three planes). Following physical activity data collection, an exit interview was conducted asking caregivers to respond to a series of questions regarding physical activity involvement of their family. Results indicate that the participants with MR tended to be higher in internal regulation (Mean=11, SD=.82), a form of extrinsic motivation related to doing something with some end in mind such as exercising for health benefits (Deci & Ryan, 2000). Lowest scores were seen on the amotivation or absence of motivation subscale (Mean=6.4, SD=2.37). Further, the participant with the highest vector magnitude value also scored the highest on the external regulation or extrinsic motivation subscale. Conversely, the participant with the lowest vector magnitude value did not show any clear preference with equally high scores on the intrinsic motivation and internal regulation subscales (value of 12 for each). Of interest in these data is the relationship between skinfold thickness and internal regulation as measured by TPMS (rs=.76, p < .05). No relationships were seen between caregiver and participant physical activity levels. Qualitative data indicate that independent living skills were the most important areas to stress in educational programs for children with disabilities. Further, exit interview responses supported participant internal regulation values in that caregivers cited social reasons for their child’s decision to stay active outside of school.Keyword(s): adapted physical activity, exercise/fitness, physical activity