Habitual snoring is associated with cardiovascular morbidity and mortality, and metabolic abnormalities such as impaired glucose homeostasis. Many studies were performed in obese Western populations. The purpose of this study was to examine the association of habitual snoring with glucose and insulin metabolism in nonobese Korean men who were free of diabetes and hypertension. A total of 2,719 men ages 40-69 years from the Korean Health and Genome Study participated in this study. Information of snoring frequency was obtained by a questionnaire and glucose and insulin levels during oral glucose tolerance test were measured. Repeated measures analysis of variance detected significant differences in the changing patterns of glucose and insulin levels at 1 hour and 2 hours between habitual snorers and nonhabitual snorers, whereas there were no significant differences in fasting blood glucose and insulin levels. Multivariate logistic regression analyses revealed that habitual snoring was independently associated with elevated 1-hour and 2-hour glucose levels and a 2-hour insulin level, respectively. The present data suggest that habitual snoring may affect glucose-insulin metabolism, independent of diabetes and hypertension, even in nonobese Korean middle-age men. Further prospective studies are needed to examine the causal relationship between habitual snoring and insulin resistance or glucose intolerance.