Data were analyzed from household interviews of four population-based cohorts comprising the Established Populations for Epidemiologic Studies of the Elderly to estimate the prevalence of prescription and nonprescription medication use among community-living elderly and to examine sociodemographic and health factors related to medication use. Prescription drugs were used by 60-68% of men and 68-78% of women. Nonprescription drugs were used by 52-68% of men and 64-76% of women. Use of prescription medications generally increased with age although use of nonprescription drugs was not associated with age. Men and women who smoked or used alcohol in the preceding year frequently took medications. Those who reported more depressive symptoms, impairments in physical functioning, hospitalizations, and had poorer self-perceived health status were most likely to take medications. However, 10-29% of respondents with fair or poor self-perceived health took no prescription medications, and 3-13% took neither prescription nor nonprescription medications. While further research appears warranted into potential overmedication of elders, particularly those with many depressive symptoms, these data suggest that studies of potential underuse among elders with poor health are equally important.