<p>In Mexico, backyard animal production system is an important source of food for domestic consumption as in many other developing countries and is characterized by a virtually nonexistent sanitary management. With the objective to evaluate the prevalence and risk factors associated with antibodies against <em>T. gondii</em> in pigs and cats from an endemic area in the Mexican tropics, a cross-sectional study was performed in 30 backyard pigs and 50 cats. Pigs and cats were blood sampled and tested by an indirect IgG ELISA to detect antibodies against <em>T. gondii</em>. Seropositivity rate in cats were of 100 % (50/50) and were identified a 75 % (23/30) of positives pigs. Results indicate a very high level of circulation of the agent in the area and a high risk of pigs to become infected. It is concluded that cats and pigs maintained under backyard had high seroprevalence to <em>T. gondii</em>. It is necessary implement sanitary measures in the management of backyard to avoid transmission to people consuming pork meat from backyard systems.</p>