In order to investigate an utilizability of a white sweet lupin (Lupinus angustifolius) seed. day-old single comb White Leghorn male chicks were fed on a commercial chick mash for the first 10 days and on a protein-free diet for the next 6 days, and then on the protein-free diet and diets containing the graded levels (10. 20 and 30%) of the lupin seed meal(LSM) for the subsequent 6 days of experimental feeding. Biological utilization of the LSM protein and energy utilization of diets were determined. and the heat production(HP) was measured by the comparative Slaughter studies. The protein intake was increased and net protein ratio(NPR) was lowered as the LSM contents of diets increased. But diet consumption. weight gain and protein efficiency ratio(PER) of birds fed LSM 20% diet were higher than those fed LSM 30% diet. True digestibility and biological value of the protein and net protein utilization of birds fed LSM 20% diet were found an increasing tendency compared with those of 30% diet. MEn and metabolizability(MEn/GE) of diets, and HP/MEn were lowered gradually as the LSM contents of diets increased while HP of birds fed LSM 30% diet was lower than those of birds fed LSM 10 and 20% diet. The result indicated that lupin seed containal antinutritional substances which affect diet consumption. biological value of protein and energy metabolism of chicks.