This study was conducted to determine the nutritional value of different sources of soybean meal as partial replacement of fish meal component of practical diets for Nile tilapia (Oreochromis niloticus) fingerlings (mean initial fish weight 22.62±0.32g). Five tested diets based on a herring fish meal (HFM) as a reference protein source were used in this study. The experimental diets were designed to contain 50% replacement of total protein content as fish meal in the control diet (100% fish meal) which equal to 61% of fish meal protein. All diets were nearly isonitrogenous and isocaloric in gross terms. The results showed that there were significant differences (P<0.05) among the final average body weight of fish at the end of the 12 weeks feeding trial. The mean final body weight of fish fed control diet, soy protein concentrate (SPC), soy flour (SF), soybean meal (SBM) and full fat soybean (FFSB) was 113.71, 100.78, 91.21, 89.97 and 85.32g, respectively. The poorest response was observed for fish fed FFSB containing diet. Similar trends were also observed in specific growth rate (SGR), feed conversion ratio (FCR), protein efficiency ratio (PER) and feed intake (FI). The viscera-somatic index (VSI) did not reflex significant differences for all fish fed the experimental diets, while results of hepatosomatic index (HSI) showed significant differences (P<0.05) among treatments. Economic analysis showed the possibility of using different sources of soy as an alternative protein source in monosex Nile tilapia feed. Diets contained 50% of total protein from SBM, FFSB followed by SF provided the best economic efficiency of fish weight gain, while diets containing FM and SPC resulted in less economic efficiency because of the high in the price of feed cost per kg weight gain. The results of the present study indicated that, the monosex Nile tilapia can be fed plant protein sources (soybeans) to replace 50% of total dietary protein or 61% of fish meal in the diets without compromising growth and feed conversion and no mortality was observed during the experimental period and the overall health appearance of fish was normal.