The tremendous potential of GIS to benefit the health care industry is just now beginning to be realized. Both public and private sectors are developing innovative ways to harness the data integration and spatial visualization power of GIS. The type of companies and organizations adopting GIS span the health care spectrum- from public health departments and public health policies and research organizations to hospitals, medical centers and health insurance organizations. GIS plays a critical role in determining where and when to intervene, improving the quality of care, increasing accessibility of service, finding more cost effective delivery modes, and preserving patient confidentiality while satisfying the needs of the research community for data accessibility.