BACKGROUND/OBJECTIVE To document the relationship between level of physical activity and quality of life in persons with spinal cord injury. DESIGN Cross-sectional investigation. PARTICIPANTS/METHODS Men (n = 32) and women (n = 30) with complete and incomplete spinal cord lesions below C6 volunteered to participate in this study. The average length of time since the onset of disability was 9 years (range, 1.5-40 years). Using an interview-formatted survey (Quality of Well-Being Scale), a measure of quality of life was obtained for each participant. Physical activity levels were determined using the Physical Activity Scale for Individuals with Physical Disabilities. RESULTS A strong positive association (r = 0.75; P < 0.05) was observed between level of physical activity and quality of life. Multiple regression analysis also showed that when level of physical activity, anatomical location of the injury, completeness of injury, and time since injury were used as explanatory variables, level of physical activity was the only significant predictor of quality of life, accounting for 56% of the total variation in quality of life. CONCLUSIONS Results from this study show that a significant and moderately strong positive relationship exists between level of physical activity and quality of life in adults with spinal cord injury. From a clinical perspective, these findings suggest that interventions aimed at promoting physical activity may be effective in improving quality of life in this population.