This experiment was carried out to determine the effect of different stocking ratios (SR) in both cultivation systems (monoculture and polyculture) of hybrid red tilapia (O. niloticus males × O. mossambicus females) and striped mullet (Mugil cephalus) on growth performance, feed utilization and body composition. Hybrid red tilapia (T) : mullet (M) were stocked at seven ratios or treatments were (1:0, 0:1, 1:2, 2:1, 1:1, 3:1 and 1:3 ), respectively. Hybrid red tilapia and striped mullet fingerlings with initial body weights of 5.37 and 5.45 g/fish, respectively. Fish fed at the start of experiment in all treatments at the rate of 6 % biomass weights then it was reduced gradually to 4% until the end of the experiment. The results showed that, hybrid red tilapia was higher than striped mullet in the most of growth performance parameters and feed efficiency under the monoculture system. Also, the results indicated that polyculture gave the highest growth performance (biomass weight or gains) compared with monoculture. The survival rate of hybrid red tilapia and striped mullet ranged between 95 – 100 and 80 – 90 %, respectively with no significant effect by different stocking ratios. The growth performance, biomass and feed efficiency increased with increasing of red tilapia ratio in each treatment. From these results it could be recommended that the polyculture system of red tilapia and striped mullet were better than the monoculture system for growth performance traits, in addition, the best stocking ratio was 3 red tilapia : 1 striped mullet in polyculture system at a density of 40 fish/m³.