The aim of the experiment was to determine the effect of rapeseed, soyabean, linseed, and fish oil as sources of polyunsaturated fatty acids in lamb diets on the fatty acid composition of intramuscular, subcutaneous and perirenal fat. Thirty fattened lambs of an average body weight of 22±3 kg were divided into five groups and fed a control diet without added oil, or experimental diets supplemented with 4% of a given oil. Linseed oil reduced (P≤0.01) the ratio of n-6 to n-3 polyunsaturated fatty acids to the desired value, whereas both soyabean or fish oil raised (P≤0.01) this ratio in intramuscular fat. Linseed oil increased (P≤0.05), but rapeseed and fish oil decreased the level of monounsaturated fatty acids in perirenal fat. None of the oils affected the fatty acid concentration in subcutaneous fat. All supplemented oils increased (P≤0.05) intramuscular CLA. The highest was from 28.8 µg/g fat in control group to 33.3, 48.2, 53.4 and 97.1, respectively, with rapeseed oil, soyabean oil, linseed oil and fish oil addition. An increased CLA concentration in perirenal and subcutaneous fat was observed when linseed oil was added to the diets.