It has been reported that consumption of CLA and EPA alters lipid metabolism. CLA contains conjugated double bonds, and EPA is an n-3 PUFA. Based on the possibility that a molecule with both of these structures might have interesting physiological effects, we prepared conjugated FA from EPA by alkaline isomerization and examined the effects of the conjugated EPA (CEPA) on lipid metabolism in rats. Rats were fed by oral gavage every day for 4 wk with 200 mg of FA including linoleic acid, EPA, CLA, or CEPA. Compared with other groups, rats fed CEPA showed a significant weight loss in epididymal adipose tissue and significant decreases in the levels of liver TAG and total cholesterol (TC), indicating reduced accumulation of lipid in the liver and adipose tissue. The plasma levels of TAG, TC, FFA, and tumor necrosis factor-alpha in rats fed CEPA were reduced, as was the activity of the FA synthesis system in the liver, whereas the FA-beta-oxidation system was activated by CEPA. These results suggest that intake of CEPA suppresses lipid accumulation in the liver and epididymal adipose tissue while increasing lipid catabolism in rats.