A seroepidemiological survey of Toxoplasma gondii infection among Atayal and Paiwan mountain aborigines and Southeast Asian laborers in Taiwan was assessed from February 1998 to July 2000 using a latex agglutination test. To determine risk factors for T. gondii infection among Taiwan aborigines, the consumption of raw meat and valley water were given particular attention in a self-administered questionnaire. The overall seroprevalence of T. gondii infection was 19.4% for Atayal, 26.7% for Paiwan, 42.9% for Indonesian, 14.7% for Thai, and 11.3% for Filipinos. No significant gender difference in seroprevalence was found among Atayals, Paiwans, Indonesians, and Filipinos (P > 0.05). In the Thai group, however, males had a higher seroprevalence than females (P < 0.001). Results of the multiple logistic regression analysis indicate a higher odds ratios (OR) with age in both aboriginal groups. In contrast, the OR was lower among older Indonesians and Thais. Those Atayals and Paiwans with a history of eating raw meat seemed more susceptible to T. gondii infection than those who had never consumed raw meat. Ethnically, a significant difference in seroprevalence was observed between Indonesians and Paiwans, Atayals, Thais, and Filipinos (P < 0.001).