Chagas disease, a major public health problem in Latin America, is caused by the protozoan parasite Trypanosoma cruzi and transmitted by hematophageous insects from the Triatominae subfamily. Control of this disease is based on domestic vector control with insecticides and improvements in housing. As with other vector-borne diseases, the identification of areas of high risk of disease transmission is a major prerequisite for the planning and implementation of cost-effective control programs. In this study, we explored the relationship between Triatoma dimidiata geographic distribution and bioclimatic factors in the Yucatán peninsula in Mexico, using geographic information systems, and developed predictive models of T. dimidiata domestic abundance and of its infection rates by T. cruzi. These predictions were then used to build the first natural transmission risk map for Chagas disease in the Yucatán peninsula, a tool that should prove very valuable for the implementation of effective vector control programs in the region.