This study was conducted to evaluate the apparent protein digestibility and amino acid availabilities of fish meal replaced with soybean meal and full fat soybean at two levels of 50% and 75% in the.Nile tiiapia fingerlings.The carcass protein, lipid and gross energy gain were improved when dietary fish meal was replaced with soybean meal or full fat soybean at the levels of 50% than 75% .Diets containing either soybean meal (50%) or full fat soybean (50%) had the highest significant (P&0.01) value for protein digestibility coefficient than the other treatments.The over all pattern of apparent amino acids, availability corresponds to that of protein digestibility -The availability of threonine from fish meal and that of methionine of soybean meal at 75% replacement level offish meal were the lowest in the respective protein sources. Cystine availabilities of fish meal and full fat soybean at 75% replacement level were low compared with other amino acids.This study demonstrates that soybean meal or full fat soybean may used as a best source of protein in combination with fish meal in the diet for Nile tiiapia at the level up to 50% of total dietary protein, in order to ensure a favorable essential amino acid profile which closely meets the requirements.