To recognize the best dietary crude protein (CP) percentage and stocking rate (SR) of monosex Nile tilapia under recirculating aquaculture system, two CP levels (25 & 32 %) and two SR (140 & 210 / m³) were used for 168 days. The obtained results revealed that feeding fish 32 % CP-diet at SR of 140 fish / m³ resulted in the best final bodyweight, average daily gain, specific growth rate, feed conversion, survival, energy utilization, and return. Whereas, 32 % CP at 210 fish / m³ was responsible for best protein productive value, body weight (with lowest inedible parts percentage), carcass protein percent (with lowest fat %), and productivity / m³. So, it could recommend feeding Nile tilapia (under similar conditions to those of the present experiment) 32 % CP-diet and stocking rate of 140 fish / m³.