This article introduces and illustrates the application of Geographic Information System technology to examine patterns of social-services use in community-based interventions. By integrating management information system data from human service agencies and publicly accessible data from the U.S. Census within a specially-referenced framework, the study illustrates that GIS analysis could help managers and planners of social services to assess the extent to which program implementation reflects adherence to a program concept and identify geographical areas with the greatest unmet service needs. The article demonstrates the application of GIS technology, based on an analysis of a city-wide community-based homelessness prevention program in Philadelphia.