Conjugated linoleic acid isomers (CLA) have been reported to exert anticarcinogenic effects, protection against atherosclerosis and decrease of body fat among others effects, in both animals and humans. However the mechanism of action of CLA remains still unknown, with various proposed pathways. Moreover previous works have reported ambiguous results and contradictory effects. The C18:2t10,c12 has been associated elsewhere to deleterious bioactivities. According to this, further data are needed to unravel the biological activities of CLA. The aim of this study was to evaluate the effects of CLA as part of the diet of adult hamsters in reversing hypercholesterolemia, a risk factor associated with atherosclerosis. The hypercholesterolemic condition was induced in male Syrian Golden hamsters, then divided into three groups receiving CLA pre-mixed in the diet (diet CLA1), administered separately (through gavage) as CLA oil, (diet CLA2), or not added (CD, control diet). All diets contained 0.1% cholesterol and were equivalent in lipid content. Blood physiological parameters, lipid profile, glucose, liver enzymes and body weight were monitored weekly. After 35 days, hamsters fed CLA2 diet reduced in great extension the body weight while CLA1 was more effective in lowering the concentration of triglycerides in plasma. Liver functions and glycemic status were not affected. The main outcomes of the present research work are that CLA in the form of oil or added to powder milk does not cause toxic effects or alter live functions or glycemia in hamsters. Furthermore, the results suggest that CLA formulated as a skimmed milk powder product can reverse hypercholesterolemic risk factors while high CLA oils is useful for weight control.