BACKGROUND AND OBJECTIVES: Insulin resistance is associated with hyperlipidemia. Recently, visceral fat adiposity is reported to be associated with insulin resistance and hyperlipidemia. We investigated insulin resistance and visceral fat adiposity in hyperlipidemic patients. MATERIALS AND METHOD: Hyperlipidemic group included 14 hyperlipidemic patients (total cholesterol > or = 220 mg/dl and triglyceride < or = 400 mg/dl) without hypertension, angina, impaired glucose tolerance and diabetes mellitus (DM). Control group included age, sex and body mass index (BMI) matched 25 healthy volunteers. We measured plasma lipid profiles and the insulin and glucose during the oral glucose tolerance test. We measured visceral fat area and abdominal subcutaneous fat area with computed tomography (CT). RESULTS: There were no differences of age, sex and BMI in both group. Total cholesterol, LDL cholesterol and triglyceride increased significantly in hyperlipidemic group. Fasting plasma glucose, insulin, area under curve (AUC) of the glucose and insulin and the Insulin / Glucose (IG) ratio increased significantly in hyperlipidemic group. Significant positive correlations were demonstrated between visceral fat area and the fasting plasma glucose, AUC of glucose and insulin at 120 minutes after glucose load. However, there was no difference in visceral fat area between both groups. After adjustment of visceral fat area, fasting plasma glucose, insulin, area under curve (AUC) of the glucose and insulin and the Insulin / Glucose (IG) ratio still remained increased significantly in hyperlipidemic group. CONCLUSION: We observed significantly increased insulin resistance in hyperlipidemic group. There was partial relationship between visceral fat area and the glucose and insulin profile. However, we did not find increased visceral fat area in hyperlipidemic group.