The perception that some diseases happen in certain places is old. The concern in studying the relation between the human being and the environment resulted in several studies of medical geography, directed to the analysis of diseases spatial distribution. This sectional study was carried out in Ribeirão Preto, São Paulo State, and aimed to illustrate, through health problems (dengue, leprosy and tuberculosis), how a Geographic Information System tool allows the identification of heterogeneous areas, providing support for the choice of strategies and specific interventions according to the need of residents, as well as, priority of resources to more vulnerable groups. The population comprised cases of dengue, leprosy and tuberculosis notified in Ribeirão Preto in 2000. Data were collected in the Health Secretary Epidemiological Surveillance of the city. In order to obtain the thematic maps, data were geo-codified with the software MapInfo 7.8 e Spring 4.3. The thematic maps showed the density distribution of dengue, leprosy and tuberculosis cases in the city as a way to complement the analysis of health information, pointing priority areas for the control of these diseases.