Hurricanes can have devastating effects on health and may directly modulate vector-borne diseases. Chagas disease is a zoonosis caused by the protozoan parasite Trypanosoma cruzi and transmitted by triatomine bugs, and the effect of hurricanes on these bugs is largely unknown. We thus performed a detailed study of the changes in Triatoma dimidiata geographic distribution and infection rates after Hurricane Isidore devastated the Yucatán Peninsula in September 2002. Bugs were collected in 34 villages from the entire peninsula, during a year, starting 3 months after the hurricane. Pre- and posthurricane bug collections were compared to assess changes. The most notable effect was a large increase in domestic abundance of T. dimidiata during the 6 months after the hurricane. This increase was maximum along the path of the hurricane. These results suggest that vector control programs should be implemented along the path of hurricanes to prevent an increase in Chagas disease transmission risk in the ensuing months.