OBJECTIVE To determine the point prevalence of painful musculoskeletal (MSK) conditions in obese subjects before and after weight loss following bariatric surgery. METHODS Longitudinal, interventional, unblended. METHODS Forty-eight obese subjects (47 women, one man, mean age 44+/-9 years; mean body mass index (BMI) 51+/-8 kg/m(2)) recruited from an academic medical center bariatric surgery program. METHODS Comorbid medical conditions; MSK findings; BMI; Western Ontario McMaster Osteoarthritis Index (WOMAC) for pain, stiffness and function; and SF-36 for quality of life. METHODS Consecutive subjects were recruited from the University Hospitals of Cleveland Bariatric Surgery Program. Musculoskeletal signs and symptoms and non-MSK comorbid conditions were documented at baseline and at follow-up. SUBJECTS completed the SF-36 and the WOMAC questionnaires. Analyses were carried out for each MSK site, fibromyalgia syndrome (FMS) and for the cumulative effect on the spine, upper and lower extremities. The impact of change in comorbid medical conditions, BMI, physical and mental health domains of the SF-36 on the WOMAC pain subscale score was evaluated. SF-36 outcomes were compared to normal published controls. RESULTS Forty-eight subjects were available for baseline and a follow-up assessment 6-12 months after gastric bypass surgery. They lost an average of 41+/-15 kg and the mean BMI decreased from 51+/-8 to 36+/-7 kg/m(2). Baseline comorbid medical conditions were present in 96% before surgery and 23% after weight loss. There was an increased prevalence of painful MSK conditions at baseline compared to general population frequencies. Musculoskeletal complaints had been present in 100% of obese subjects before, and 23% after weight loss. The greatest improvements occurred in the cervical and lumbar spine, the foot and in FMS (decreased by 90, 83, 83 and 92%, respectively). Seventy-nine percent had upper extremity MSK conditions before and 40% after weight loss. Before surgery, 100% had lower extremity MSK conditions and only 37% did after weight loss. The WOMAC subscale and composite scores all improved significantly, as did the SF-36((R)). Change in BMI was the main factor impacting the WOMAC pain score. CONCLUSIONS There was a higher frequency of multiple MSK complaints, including non-weight-bearing sites compared to historical controls, before surgery, which decreased significantly at most sites following weight loss and physical activity. These benefits may improve further, as weight loss may continue for up to 24 months. The benefits seen with weight loss indicate that prevention and treatment of obesity can improve MSK health and function.