The study determined the influence of the addition of 5% linseed oil (LO) and 2 μg Se as selenate (SeVI) per g of diet on body mass gain (BMG), feed conversion efficiency (FCE), and concentrations of fatty acids (FA), especially conjugated linoleic acid (CLA) isomers, in the liver, heart, m. longissimus dorsi (MLD), m. biceps femoris (MBF), subcutaneous fat (SF), perirenal fat (PF), and intermuscular fat (IF) of sheep. The diets with LO, regardless of the presence of SeVI, increased BMG, FCE, and the mass of MBF,MLD, and the liver. The LO treatment increased the concentration of total CLA isomers in the liver, SF, PF, and MLD in comparison with the control. Dietary SeVI increased the capacity of Δ9-desaturation in all adipose tissues as the concentration of cis9,trans11CLA increased in these tissues.