A cross-sectional study was conducted from June 2013 to August 2015 to determine the seroprevalence and possible risk factors for human Toxoplasma gondii infection in Korean, Manchu, Mongol and Han ethnic groups in eastern and northeastern China. A total of 1842 serum samples, including Han (n = 802), Korean (n = 520), Manchu (n = 303) and Mongol (n = 217) groups, were analysed using enzyme-linked immunoassays to detect IgG and IgM T. gondii antibodies. The overall T. gondii IgG and IgM seroprevalences were 13·79% and 1·25%, respectively. Of these groups, Mongol ethnicity had the highest T. gondii seroprevalence (20·74%, 45/217), followed by Korean ethnicity (16·54%, 86/520), Manchu ethnicity (13·86%, 42/303) and Han ethnicity (11·35%, 98/802). Multiple analysis showed that the consumption of raw vegetables and fruits, the consumption of raw/undercooked meat and the source of drinking water were significantly associated with T. gondii infection in the Han group. Likewise, having a cat at home was identified as being associated with T. gondii infection in the Korean, Manchu and Mongol groups. Moreover, the consumption of raw/undercooked meat was identified as another predictor of T. gondii seropositivity in the Mongol group. The results of this survey indicate that T. gondii infection is prevalent in Korean, Manchu, Mongol and Han ethnic groups in the study region. Therefore, it is essential to implement integrated strategies with efficient management measures to prevent and control T. gondii infection in this region of China. Moreover, this is the first report of T. gondii infection in Korean, Manchu, and Mongol ethnic groups in eastern and northeastern China.