This study examined the impact of environmental factors and caregiver attitudes on exercise participation in adults with cerebral palsy using a social-cognitive model. The sample included 83 adults with cerebral palsy (47.0% males and 53.0% females). Hierarchical regression analysis was conducted with exercise frequency as the dependent variable. Independent variables included personal characteristics of persons with cerebral palsy (age, level of mental retardation, health status, mobility, and arm/hand limitation), type of residence, exercise facility access, and caregiver-perceived benefits of exercise for people with cerebral palsy. The significant determinants of exercise participation were the caregiver's perceived benefits of exercise for persons with cerebral palsy and the type of residence. When caregivers perceived greater benefits of exercise, adults with cerebral palsy were likely to exercise more frequently. Non-nursing home residents were more likely to exercise than nursing home residents. This difference was related to differences in the caregivers' perceived benefits of exercise and not because of the personal characteristics of the residents or access to the exercise facility. Results of this study point to the need to inform and educate caregivers about the benefits and importance of exercise for adults with cerebral palsy.