Journal of Medical Systems, Vol. 28, No. 3, June 2004 ( C  2004) Geographic Information Systems in Public Health and Medicine Ross M. Mullner, 1,3 Kyusuk Chung, 2 Kevin G. Croke, 1 and Edward K. Mensah 1 Geographic information systems (GIS) are increasingly being used in public health and medicine. Advances in computer technology, the encouragement of its use by the federal government, and the wide availability of academic and commercial courses on GIS are responsible for its growth. Some view GIS as only a tool for spatial research and policy analysis, while others believe it is part of a larger emerging new science including geography, cartography, geodesy, and remote sensing. The specific advantages and problems of GIS are discussed. The greatest potential of GIS is its ability to clearly show the results of complex analyses through maps. Problems in using GIS include its costs, the need to adequately train staff, the use of appropriate spatial units, and the risk it poses to violating patient confidentiality. Lastly, the fourteen articles in this special issue devoted to GIS are introduced and briefly discussed. KEY WORDS: geographic information systems; spatial analysis; mapping. INTRODUCTION Today, geographic information systems, or GIS, are increasingly being used to investigate diverse public health and medical problems. For example, environmental health researchers are using GIS to conduct risk analyses of the spatial diffusion of air and water pollutants. Epidemiologists are using GIS to investigate possible etio- logical risk factors of various acute and chronic diseases. Community health science researchers are using these systems to study the disparities in disease and mortality rates among various ethnic and racial groups. Emergency planning and management researchers are studying their anticipated responses to possible natural disasters and terrorist attacks at various geographic locations. Health administration researchers are analyzing the demographic, socioeconomic, and medical characteristics of indi- viduals in hospital service areas to determine the optimal mix and location of new health centers, satellite, and mobile clinics. (1–5) 1 School of Public Health, University of Illinois at Chicago, Chicago, Illinois. 2 College of Health Professions, Governors State University, University Park, Illinois. 3 To whom correspondence should be addressed at Ross Mullner, 10301 S. Kostner, Oak Lawn, Illinois 60453; e-mail: rmullner@comcast.net. 215 0148-5598/04/0600-0215/0 C  2004 Plenum Publishing Corporation