AIMS/INTRODUCTION: The investigation of the influence of dietary fiber intake on the incidence of type 2 diabetes in a general Japanese population. MATERIALS AND METHODS: A total of 1,892 individuals aged 40-79 years without diabetes at baseline were prospectively followed up for 14 years. The glucose tolerance status of participants was defined by a 75-g oral glucose tolerance test with the 1998 World Health Organization criteria. Dietary fiber intake was estimated by a semiquantitative food frequency questionnaire and divided to quintile levels separately by sex. A Cox proportional hazards model was applied for computing the hazard ratios and their 95% confidence intervals for the incidence of diabetes. RESULTS: During the follow-up period, 280 participants had developed diabetes. The age-adjusted cumulative diabetes incidence decreased significantly with higher total dietary fiber intake (P-for trend = 0.01). Participants in the highest quintile of total dietary fiber intake had a 0.53-fold (95% confidence interval 0.31-0.90) lower risk of developing diabetes than those in the lowest quintile after for the adjustment with potential confounding factors. Total dietary fiber intake showed a moderate positive correlation to the intake of soybean and soybean products, green vegetables, and other vegetables. Similar associations with diabetes and food sources were observed for both of the soluble and insoluble dietary fiber intake. CONCLUSIONS: The present study showed that higher dietary fiber intake was associated with a lower risk of type 2 diabetes in a general Japanese population. The intake of high dietary fiber foods might be useful for diabetes prevention.