['To investigate whether fatty liver per se is an independent risk factor of incident type 2 diabetes mellitus (T2DM) in Koreans.', 'We examined the clinical and laboratory data of 5372 non-diabetic participants (3670 men and 1702 women; age 46.8 +/- 8.4 years, range 20-79 years) who underwent voluntary medical check-ups in 2000 and follow-up examinations in 2005.', 'Two hundred and thirty-three participants (4.3%) developed T2DM after 5 years. Univariate analysis showed that the development of diabetes was associated with: male sex; family history of diabetes; smoking; older age; higher body mass index (BMI), systolic and diastolic blood pressure, fasting plasma glucose (FPG), hepatic enzymes, total cholesterol and triglycerides; lower HDL cholesterol; and the presence of fatty liver on ultrasonography at baseline. In multiple logistic regression models, after adjusting for age, sex and alcohol consumption, patients with fatty liver were at significantly higher risk of developing T2DM compared to those without fatty liver [relative risk (RR) 3.92, 95% confidence interval (CI) 2.89-5.31]. After further adjustment for smoking, BMI, triglycerides, HDL cholesterol, FPG, alanine aminotransferase and ultrasonographer, fatty liver remained significantly associated with the development of T2DM (RR 1.51, 95% CI 1.04-2.20). Patients with moderate to severe fatty liver had higher risk ratios than patients with mild fatty liver. Exclusion of frequent drinkers did not attenuate the association.'] Is fatty liver an independent risk factor for the development of Type 2 diabetes in Korean adults?