Non-alcoholic fatty liver disease (NAFLD) is usually associated with insulin resistance, central obesity, reduced glucose tolerance, type 2 diabetes mellitus and hypertriacylglycerolaemia. The beneficial effects of resveratrol on metabolic disorders have been shown previously. The aim of this study was to evaluate the effects of resveratrol supplementation on cardiovascular risk factors in patients with NAFLD. In this randomised double-blinded placebo-controlled clinical trial, fifty NAFLD patients were supplemented with either a 500-mg resveratrol capsule or a placebo capsule for 12 weeks. Both groups were advised to follow an energy-balanced diet and physical activity recommendations. resveratrol supplementation reduced alanine aminotransferase (ALT) and hepatic steatosis significantly more than placebo (P<0·05). BMI, waist circumference, serum aspartate aminotransferase, bilirubin, HDL-cholesterol and apo a1 were reduced significantly in both groups (P<0·05); however, there were no significant differences between the two groups (P>0·05). There were no significant changes in blood pressure, insulin resistance markers and TAG in either group (P>0·05). Our data have shown that 12-week supplementation of 500 mg resveratrol does not have any beneficial effect on anthropometric measurements, insulin resistance markers, lipid profile and blood pressure; however, it reduced ALT and hepatic steatosis in patients with NAFLD.