Stroke is the leading cause of disability in older Americans, and survivors tend to be sedentary, which risks loss of functional gains achieved during rehabilitation and increases cardiovascular risk. Studies of motivation to exercise in older adults suggest that self-efficacy and outcome expectations a re key determinants of initiation and adherence to exercise programs. This study tested a theoretical model of physical activity in stroke survivors. A survey of exercise beliefs and patterns was sent to National Stroke Association stroke support groups. Responses from 312 stroke survivors (mean age 63 years, 57% female, 70% White) indicated that only 31% exercised four times weekly. Self-efficacy and outcome expectations for exercise, before exercise history, and physician recommendation all directly and indirectly influenced self-reported exercise behavior and accounted for 33% of the total variance in exercise behavior. Model testing supported the theory and the model fit the data. Interventions to strengthen self-efficacy and outcome expectations for exercise, along with reminders for clinicians to encourage regular exercise programs, may increase the likelihood of initiating and maintaining an exercise program, potentially improving physical function and cardiovascular fitness in this population.