Little is known of the seroprevalence of Toxoplasma gondii in bred cynomolgus monkeys (Macaca fascicularis) in China. In the present survey, 240 serum samples of cynomolgus monkeys from 4 nonhuman primate centers in Guangxi Zhuang Nationality Autonomous Region (GX), and 120 serum samples from 2 nonhuman primate centers in Guangdong Province (GD) were obtained, and the modified agglutination test (MAT) was performed to assay for anti–T. gondii antibodies. Antibodies to T. gondii (MAT titer of 1∶16 or higher) were found in 0 of 120 (0/120) samples in GD, and 5 (2.1%) of 240 sera with titers of 1∶16 in 1, 1∶64 or higher in 4 in primate centers from GX. The total prevalence of T. gondii in bred cynomolgus monkeys was 1.4% (5/360, MAT titer ≥ 1∶16) in southern China according to our investigation. To our knowledge, this is the first seropositive report in China on the prevalence of anti–T. gondii antibodies in bred cynomolgus monkeys using MAT.