Four protein levels (25, 30, 35 and 40%) were used for Tilapia and Common Carp feeding. The results showed that Tilapia fish contained higher total lipids and cholesterol levels than Carp fish. The increment of protein level of the fish ration raised up their total proteins phos pholipids and cholesterol and lowered the total lipids contents of both Tilapia and Common Carp fish. The data also revealed that the four formulated diets affected the cholesterol content of both Tilapia and Carp fish livers. The formulated diet (cottonseed cake-meat maeal) gave the highest cholesterol level in the livers of the two examined species. The results also indicated some differences between the two tested species in some parameters which were higher in Tilapia than Car