Starea and urea were used in two experiments as nitrogen supplements to maize silage plus maize meal for early weaned lambs. Maize meal was fed at a level of 1 and 2 per cent of mean body mass in Experiment 1 during 1976 and Experiment 2 during 1977 respectively. In both experiments maize silage was fed ad lib. In the first four treatments within both experiments, Starea supplied 40, 3D, 20 and 10 per cent and in the following three treatments urea supplied 30, 20 and 10 per cent of the total nitrogen in the rations. Any further nitrogen deficiencies in the rations were supplied by natural protein sources so as to bring the crude protein content up to 14 per cent of the dry matter. Although there was a tendency towards poorer growth performance as NPN increased in the rations, this difference was not significant. There was a significant improvement in daily growth rate when maize meal was supplemented at 2 per cent of body mass (P <0,0 1). No significant differences between treatments occurred for carcass characteristics. A significantly higher slaughtering percentage and carcass grading occurred in the second experiment (P< 0,01) as a result of the higher maize addition Carcass income above feed cost, in almost all the groups, was more than twice the feeding cost. In the first experiment there was a strong tendency towards a higher income over feeding cost as the level of NPN in the rations decreased. This resulted from the better growth obtained with rations which were lower in NPN content. No clear pattern was evident for the second experiment in this regard.