Data from the US Health and Nutrition Examination Survey (HANES I) of 1971-1975 confirm the high prevalence of musculoskeletal impairments among United States adults. Musculoskeletal impairments tend to be more prevalent among older persons, and persons with less education and with lower annual family incomes. Prevalence rates are slightly higher in females than in males, while Whites and non-Whites are affected with almost equal frequency. Among persons reporting a history of musculoskeletal symptoms, those who have some disability tend to be older, non-White, of lower education and income, and widowed, separated, or divorced. Persons with multiple parts of the body involved, or reporting that their symptoms are due to accident or injury are also especially likely to report disability. Taken as a whole, the data suggest that medical, social, and economic factors all play a role in determining whether a person with musculoskeletal impairment goes on to develop disability related to his or her impairment.