This study examined the implications of potential Medicare coverage for the use of preventive services by analyzing current use and and the determinants of that use by the elderly. Trends in available data suggested that the use of preventive services varies widely according to the type of service and that the rates of use of specific services show a high level of consistency across studies, despite methodological differences. Data also indicated that if an elderly person receives any preventive services, he or she is likely to receive multiple services. An analysis of data for the over 65 population in the 1982 National Health Interview Survey found that the probability that an elderly person used each of five selected preventive services (glaucoma screening, eye examinations, blood pressure measurement, breast examinations, and Pap smears) was consistently related to: (1) being male (for the three services available for men and women); (2) being younger; (3) having more education; (4) having greater family income; (5) having health insurance in addition to Medicare; (6) living in a metropolitan area; and (7) having spent more days in bed during the previous year. The implications of this study suggest that reducing patients' out-of-pocket expenses for preventive services through Medicare would probably increase the percentage of elderly receiving preventive care; Medicare coverage of preventive services may indirectly increase the use of preventive services; and expansion of Medicare to cover preventive procedures will represent an immediate boost in the program's financial obligations. (LLL)