Providing appropriate health services to the elderly is emerging as one of the major challenges of this decade. Using the theoretical framework developed by Andersen and Aday, this study attempts to improve our understanding of those factors which inhibit or facilitate elders' use of health services. The data come from a 1974 statewide random probability sample of 1,625 noninstitutionalized elders 65 years of age or older living in Massachusetts. Regression analysis is used to study the effects of predisposing, enabling, and need characteristics on the use of five health services: hospitals, physicians, dentists, home care, and ambulatory care. The model explains from 5% to 27% of the variance in health service utilization. Need characteristics, in general, account for most of the explained variance.