Fusarium moniliforme was cultured semicontinuously on a carob medium in a 14-liter fermentor (8.5-liter working volume). The growth medium provided 2.4% carob sugar, 0.72% NH4H2PO4, and 0.03% MgSO4-7H2O. The biomass harvest was 8.8 g/liter per day. Ninety percent of the sugars were consumed, and the pH dropped from 5.9 to about 3.7. The crude protein (N X 6.25) of the spray-dried mycelium was 380 g/kg, 300 g/kg for the true protein (Lowry), and 4.8 g/kg for the (Folin-Denis) tannic acid. The mycelium was evaluated nutritionally with the weanling rat as experimental animal. The protein efficiency ratio and net protein utilization values for the unsupplemented mycelium were 1.15 and 0.42, respectively, and for the mycelium supplemented with DL-methionine (5 g/kg) they were 2.31 and 0.72, respectively. No growth depression was observed in the experimental rats, and on dissection of the carcasses the internal organs were found to be normal.