The study examined the role played by informal (i.e., family, kin, neighbors, friends) and quasiformal (i.e., church-sponsored) support systems in predicting, enhancing, or inhibiting use of social services by Hispanic elderly. Thirty-seven variables and data selected from a 1979-1980 15-state survey of 1,805 noninstitutionalized Hispanic individuals aged 55 and over were categorized by the Andersen-Newman model of service use, which conceptualizes the individuals demand for services as a function of relationships among three factors: (1) predisposing (related to demographic, social, and belief characteristics); (2) enabling (related to availability and accessibility of community and family resources); and (3) need (related to perceived need and motivation). The path analysis method was used to ascertain relative importance and interrelationships of the variables. Knowledge of social services, perceived need for care, family income, self-rated health status, and ethnicity were found to be the most important determinants of social service use. Informal and quasiformal support systems affected use of services by contributing to the development of awareness of service availability and information about use, but took on differential levels of importance for various subgroups of the older Hispanic population. Problems for future research include examination of the types and sources as well as the frequency of support. References, path model diagrams and a zero order correlation matrix are appended. (LFL)