Abstract: The effects of carnos ine on growth performance of tilap ia (Oreochromis niloticus @O1aureus ) were investigated1360 tilapiawere randomly allocated into 4 treatments in triplicate aquariumswith 30 fishes per aquarium1Group A wasfed with basic diets as the control group.D iets of group B, C and D were supplemented w ith 50, 100 and 200mg/kgcarnosine respectively.The expermient lasted for 60 days1The results showed that the body weight and body length of tila p ia in the group supplemented with carnos inewere higher than that in the control group, and at the end of the tria,l thebodyweight, RSGR and RLGR of tilapia in the group of low2dosage carnos ine ( 50mg/kg) were s ign ificantly higher thanthe controlgroup(p 0105).D iets inclus ion of carnosine could mi prove the specific activities ofT2AOC, SOD and GSH 2Px in muscle of tilapia, but had a trend of debasing CAT act ivity1On the 20d, the specific act ivities of SOD in the group of lowdosage carnos ine ( 50mg/kg) and medium dosage carnosine ( 100mg/kg) were s ign ificantly higher than that in the controlgroup (p< 0105) respectively, and the specific activit ies of CAT in the group of h igh2dosage carnos ine ( 200mg/kg) wass ignificantly lower than that in the control group ( p< 0105) 1On the 40d, the specific activities ofGSH Px in all groupssupplemented with carnos inewere significantly higher than that in the control group (p< 0105).The results indicated thatthe diet supplemented with carnos ine of appropriate dosage ( 50mg/kg) could mi prove the ant ioxidation inmuscle, the hormone levels in serum, and growth of tilapia.