SUMMARY Cross-sectional and longitudinal evidence strongly indicate that obesity is related to physical impairment and joint pain, particularly in the lumbar spine, sacroiliac and knee joints. What is most disturbing is that obese children under 15 years are now reporting joint pain and cannot perform functional tasks as well as their nonobese counterparts. As the prevalence of obesity rises, so do the rates of musculoskeletal disease and physical dysfunction. Functional tasks that involve supporting or transferring body weight are typically painful and difficult to perform. Of most concern is that some of these tasks are simply impossible depending on the severity of obesity. As a consequence, the individual's quality of life suffers. A BMI of 35 kg/m(2) is emerging as the threshold at which functional impairment rates rise dramatically. To restore functional independence and optimize functional gains over the long term, a combination of treatments for the obese patient with joint pain may be effective. The initial use of physical therapy, pain medications or joint viscosupplementation, coupled with diet, exercise, or bariatric surgery are options for weight loss and reduction of pain symptoms. Irrespective of age, weight loss can reduce or eliminate joint pain. As body weight is reduced, so should the reliance on medication with a concomitant improvement in functional mobility.