An experiment was carried out to investigate the effect of supplementation of spray-dried beef tallow (BT) on fat nutrition , and to discuss the possibility of improving meat quality by stimulation of fat deposition in the muscles of fattening sheep. There were no clear differences in growth rate between the BT-supplemented group and control group, so the feed efficiency was not improved by addition of BT in the present experiment. Plasma triglyceride (TG) level was relatively steady along with their growth in the control group, but a little high in the BT-supplemented group at an early stage of the experiment. The plasma cholesterol level tended to be higher(P<0.05) in the BT-supplemented group as compared with that in control at 0, 1 and 3 months after the initiation of experiment. The moisture content of the carcass decreased (P<0.05) after feeding BT diet as compared with that after feeding control diet, and, on the contrary, the contents of crude fat tended to increase in lambs fed the BT diet. As a result, the meat (such as the loin) tended to contain more fat in lambs fed the diet with BT than in control. These findings indicate a possibility that the BT treatment, such as spray-drying as in this study, can be used as an energy source to stimulate fat deposition in the muscles of fattening sheep.