The reservoir capacity of dogs for Trypanosoma cruzi infection was analyzed in the city of Campeche, an urban town located in the Yucatan peninsula in Mexico. The city is inhabited by ~96,000 dogs and ~168,000 humans; Triatoma dimidiata is the only recognized vector. In the present study, we sampled 262 dogs (148 stray dogs and 114 pet dogs) and 2800 young people (ranging in age between 15 and 20 years old) and tested for T. cruzi antibodies by enzyme-linked immunosorbent assay, Indirect Immunofluorescence, and Western blotting serological assays. Seroprevalence in stray dogs was twice higher than in pet dogs (9.5% vs. 5.3%) with general seroprevalence of 7.6%. In humans, the observed seroprevalence was 76 times lower than in dogs (0.1% vs. 7.6%, respectively). Western blotting analysis showed that dogs' antibodies recognized different T. cruzi antigenic patterns than those for humans. In conclusion, T. cruzi infection in Campeche, Mexico, represents a low potential risk to inhabitants but deserves vigilance.