The effect of different fat sources and amounts in diets on the fatty acid composition of meat was estimated in an experiment on 24 lambs. The basal diet consisting of meadow hay and concentrate (60:40) for control animals was supplemented for experimental animals with 6% linseed oil, rape seed oil, or hydrogenated rape seed oil. Feeding lambs with the 6% addition of linseed oil, rape seed oil or hydrogenated rape seed oil to the diet had no significant influence on total saturated fatty acid content in meat. The addition of 10% hydrogenated rape seed oil significantly (P < 0.05) decreased the level of miristic acid in meat. Addition of rape seed oil increased (P<0.05) the level of stearic acid in comparison with groups that received linseed or hydrogenated rape seed oil. Statistically significant (P < 0.05, P < 0.01) increases in total n-3 polyunsaturated fatty acids (PUFA) in comparison with the control group were found when rape seed or linseed oils were added to the diet. Rape seed oil also caused a significant (P < 0.01) increase in total n-6 PUFA in comparison with groups receiving linseed or hydrogenated rape seed oils. The results obtained in the experiment demonstrate that feeding lambs diets supplemented with fats of vegetable origin can alter the fatty acid composition of meat, with potential benefits to human health.