In this paper background, objectives, methodology and a few preliminary findings of a comparative epidemiological study of mental disorders among four aboriginal groups in Taiwan are presented. The study includes both a cross-sectional sample survey (N = 993) and prospective cohort studies involving psychoses, minor psychiatric morbidity, alcoholism, suicide, and accidental death. The total response rate to the sample survey was 98·3%; respondents were found to be representative. A preliminary analysis found very high rates of death from suicide, accidents and chronic liver and lung disease with a previous history of alcoholism in many of these deaths. Implications of these findings and studies of risk factors of all these health problems and their relationships are discussed.