Four groups of 44 suckling lambs (30 male and 14 female) were given supplementary feeds: meadow hay and a concentrate with barley containing: 162, 135 or 103 g crude protein in dry matter (groups H, M and L, respectively) or a mixture with oats, containing 138 g crude protein, group C. Restricting crude protein in the mixture to about 14% in DM did not have a detrimental effect on the growth of lambs, but when the mixture containing about 10% protein was given, the body weight gain of male lambs significantly declined. From day 28 of life to weaning at 89-93 days, the body weight gains of ewes did not differ among groups and equaled 120-132 g per day, while male lambs gained 142^a, 147^a, 126^ab and 115^b g (P<0.05) daily in groups C, H, M and L, respectively. The intake of dry matter from creep feed by suckling lambs was markedly lower than given in the IZ standards.