To investigate the relation of alcohol use and cigarette smoking to glucose tolerance status, we performed a cross-sectional study of 3038 male officials aged 46-59 years in the Self-Defense Forces. Glucose tolerance status was determined by a 75-g oral glucose tolerance test. A self-administered questionnaire was used to ascertain alcohol use, smoking habits, and other lifestyle characteristics. Statistical adjustment was made for parental history of diabetes, body mass index, and leisure-time physical activity. Alcohol use was positively associated with impaired fasting glucose, impaired glucose tolerance, and type 2 diabetes mellitus each. The association was dose-dependent, with odds of each category of glucose intolerance increased even among those with moderate alcohol use. Cigarette smoking was not related to any categories of glucose intolerance. Alcohol use may confer increased risks not only of type 2 diabetes mellitus but also of preceding glucose intolerance status. Smoking does not seem to deteriorate glucose tolerance.