In Japan, the incidence of type 2 diabetes mellitus (T2DM) is increasing for several reasons, including increased consumption of sugar-sweetened beverages (SSBs). However, whether SSBs cause T2DM by excess of energy production resulting in obesity remains unclear. Therefore, the present study was designed to evaluate the effects of SSB intake on the development of T2DM in subjects with impaired glucose tolerance (IGT). Ninety-three subjects (30 males and 63 females) with IGT aged 40-69 y and residing in the Mihama district (southern Mie Prefecture, Japan) were included in the study. The mean observational period was 3.6 y. All subjects underwent the 75-g oral glucose tolerance test (OGTT) and completed a lifestyle questionnaire survey related to SSB intake. OGTT results and SSB intake were evaluated before and after the observational period. In addition, the correlation between SSB intake and development of T2DM was investigated. Of the 93 subjects, 20 (21.5%) developed T2DM (T2DM group) and demonstrated a significantly high SSB intake compared with the group that did not develop the disease (non-T2DM group). The odds ratio for the incidence of T2DM based on SSB intake was 3.26 (95% confidence interval, 1.17-9.06). The body mass index (BMI; kg/m(2)) and the homeostasis model assessment for insulin resistance (HOMA-R) values was significantly higher in the T2DM group than in the non-T2DM group, while the insulinogenic indices were significantly lower in the former than in the latter group. The sum of insulin secretion levels during OGTT was not significantly different between groups. SSB intake correlated with the predisposition for developing T2DM, possibly by influencing body weight, insulin resistance, and the ability of the pancreatic beta cells to effectively compensate for the insulin resistance.