A feeding trial was conducted to evaluate the effect of replacing soybean meal diet with fermented cottonseed meal  (FCSM) on the growth performance, feed utilization, body composition and  economical evaluation  of Nile tilapia fingerlings at rates  (20, 40, 60, 80 and 100% FCSM for T1, T2, T3, T4 and  T5, respectively. The basal diet was designed to contain (FCSM-0%) as a control).  Three hundred and sixty Nile tilapia (Oreochromis niloticus) fingerlings with initial weight of 3.5 ± 0.12 g were divided into six groups (20 fish per tank, Triplicate per treatment). Fingerlings Nile tilapia were hand-fed to visual satiation at two meals per day for 90 days. Fish were fed diets containing different levels of FCSM had no significant differences regarding survival. Final weight, Weight gain, SGR and PER were significantly higher in group of fish on T5and T4 groups, respectively. FCR was the lowest in T5 (100%) and T4 (80%) replacement of soybean meal with fermented cottonseed meal compared with the control group and other experimental dieys. Feed and protein intake were significantly highest in group of fish fed on control and T1diets and the lowest in group of fish fed on T5and T4. Body protein significantly increased with increasing level of incorporation of fermented cottonseed meal in the diets. These results indicated that incorporation of fermented cotton seed meal into fingerlings Nile tilapia fingerlings diets reduced the price of one kg diet to 82.93, 72.93, 64.71, 57.66 and 61.25% for the T1, T2, T3, T4 and T5, respectively compared to the control group (100% of the price). . In conclusion, fermented cotton seed meal can be replaced soybean meal at levels 80 or 100% without negative effects on growth performance and feed utilization of Nile tilapia fingerlings under experimental conditions.