Past research has produced contradictory findings on characteristics that differentiate elderly users of formal assistance from non-users. This article describes a study designed to clarify influences on service utilization by (a) examining an inclusive set of independent variables within a multivariate framework, and (b) systematically assessing use by type of service program. Findings indicate that traditionally studied demographic and functional capacity variables have very little predictive power in relation to service use. Knowledge of and orientation to the formal service system, in contrast, stand out as important determinants of use, especially in programs for the well elderly. Implications for both research and program development are discussed.