Objectives: With reference to the hypothesis of association between central nervous system infections and schizophrenia, in this study the relationship between Toxoplasma gondii infections and schizophrenia was studied. Method: In this case-control study, the serums of 104 inpatient schizophrenic patients admitted to  22 Bahman Hospital in Qazvin, Iran and 114 matched control subjects were examined. IgG and IgM specific antibodies to Toxoplasma gondii were detected using enzyme-linked immunosorbent assay (ELISA). Data were analyzed using c² test, t-test and Fisher exact test. Results: 55.3% of the cases and 50.9% of the controls were seropositive for IgG specific antibodies to Toxoplasma gondii and the differences were not statistically significant. The proportion of seropositive subjects was significantly lower in the first-episode patients (33.3%) than those in the next episodes (59.8%) (P<0.05). Moreover, 14.6% of the cases and 20% of the controls were seropositive for IgM specific antibodies to Toxoplasma gondii. However, the differences were not statistically significant. Conclusion: An epidemiological association between Toxoplasma gondii infections and schizophrenia was not observed.