Statins have multiple actions, independent of their classical effects on lipoproteins. The data about the effects of statins on insulin resistance is controversial. This study was designed to search the statin effects on nondiabetic dyslipidemic patients. Thirty-five (17 male, 18 female) consecutive dyslipidemic patients 54.25 +/- 8.81 yr were enrolled in the study. After a standard follow-up period of lifestyle modification, the patients were given fluvastatin 40 mg/d for 8 wk. Serum analyses were done both before and after treatment. Insulin resistance was assessed by homeostasis assessment model (HOMA). Fasting plasma triglyceride, total and LDL cholesterol, fasting insulin, and HOMA index were significantly reduced and HDL cholesterol was improved after fluvastatin treatment. HOMA-IR was not correlated with triglycerides, LDL, HDL, or total cholesterol levels. The same situation was present for both fasting plasma insulin and fasting plasma glucose levels. Also age was not associated with HOMA-IR and fasting plasma insulin levels. As a conclusion, the present study indicates that fluvastatin treatment improves insulin resistance in dyslipidemic patients who do not have diabetes or impaired fasting glucose. Also, the effect of fluvastatin on insulin resistance is not associated with the lowering of triglycerides. The latter finding indicates that the effect of statins on insulin sensitivity may not be related with the lowering of triglycerides in dyslipidemic patients.