1. The nutritional value of tempeh in comparison with that of unfermented soybeans was studied in rat feeding experiment. It was observed that the PER value of tempeh (fresh or stored) was not significantly different from that of the unfermented soybeans (fresh or stored). 2. The peroxide value of the oil of stored tempeh powder was only 10% of that of stored soybean powder. Red blood cells of rats receiving tempeh were less than 20% in hemolysis by dialuric acid whereas hemolysis was 100% for the rats receiving the un-fermented soybeans. Serum tocopherol was 0.14±0.05mg/dl in the former group, but 0.07±0.05mg/dl in the latter. Liver TBA values were 0.20±0.05 O. D./g and 0.65±0.13 O. D./g in the tempeh and the unfermented soybeans group, respectively. 3. Subsitution of whole egg for tempeh to supply 30% of protein in the diet improved the quality of the protein as measured by the protein efficiency ratio. An equal improve-ment was accomplished by supplementation of tempeh with lysine, methionine, and threo-nine in such amounts as the level of these amino acids equal to that in the tempeh-egg diet.