A high-sucrose diet induces insulin resistance and dyslipidemia in normal rats. The purpose of the present study was to investigate effects of a high-sucrose diet to glycolipid metabolism in Zucker Diabetic Fatty (ZDF) rat. Male ZDF rats were fed with a high-sucrose (68%) diet from 6 to 18 weeks of age. In biochemical analyses, the glucose levels did not change as compared with those in standard diet-fed rats, but the total cholesterol levels were elevated during the experimental period. In pathological analyses, the relative liver weight increased by about 2-fold as compared with that in standard diet-fed rats, and severe fatty change was observed by high-sucrose feeding. A high-sucrose diet induces fatty liver, but not deterioration of diabetes mellitus in ZDF rats. High sucrose-fed rats are considered to be very useful to determine the relationship between hepatic insulin resistance and diabetes mellitus.