Purpose: To evaluate the measurement structure of the "Physical Activity Scale for Individuals With Physical Disabilities" (PASIPD) as an assessment tool of lifestyle physical activities for people with severe mental illness. Method: A quantitative descriptive research design using factor analysis was employed. A sample of 72 individuals with severe mental illness was used to examine the factorial structure of the PASIPD, which contains 12 items and 5 factors. Results: Principal components analysis results indicate that the 5-factor structure of the PASIPD can be replicated with people with severe mental illness, which include light/moderate recreation and physical activity, housework, vigorous sport and recreation, lawn and garden work, and occupation. Conclusions: The results underscore the importance of increasing lifestyle physical activity levels among this population, which requires increased attention in the development of measurement tools and interventions for these activities.