Extensive research have indicated that commercial conjugated linoleic acid (CLA), fed to laboratory animals, showed several health-related properties. The objective of this study was to assess the effect of CLA on serum lipid profile, plasma malondialdehyde and liver fatty profile in Wistar rats fed for 23 d. The experimental diets were: I-AIN-93G - control (C), II- AIN-93G diet + 1.0% CLA. The CLA oil contained 600 g CLA/kg, with equal representation of cis-9,trans-11 and trans-10,cis-12 CLA isomers. The experimental treatments had no effect on rats body weight, total cholesterol, HDL, LDL+VLDL and malondialdehyde. The triacylglycerol (TG) was significantly decreased after CLA supplementation. Liver weight, fat and histology were unchanged in CLA group. Liver cholesterol was insignificantly decreased in CLA diet. Dietary treatments had significant effects of on proportions of SFA and MUFA and PUFA in liver. In conclusion, CLA decreases serum TG. Additionally, liver fat composition were changed after CLA supplementation