Dietary CLA increased triglyceride, total cholesterol, and HDL cholesterol levels in plasma. The increased plasma triglyceride level could be caused by increased fatty acid synthesis in liver after CLA feeding, because the activity of fatty acid synthase in liver increased after dietary CLA treatment. Dietary CLA changed fatty acid composition of feces, but had no effect on fat content. Comparing to the linoleic and linolenic acids available in diets, ratios for their excretion into feces in CLA treated birds were significantly higher than those in control diet. Liver weight of broilers significantly increased after CLA feeding, but there was no difference in liver fat content among the different CLA treatments. CLA treatment did not influence total free fatty acid content in plasma, while there was significant difference in composition of free fatty acids. Dietary CLA reduced the content of linoleic and arachidonic acids in both plasma and liver.