Abstract: An 8-week feeding trial was conducted to study the effects of acidifier on growth performance and feed utilization of tilapia. Four hundred and eighty tilapia juveniles with an average body weight of 5.350.02 g were randomly allocated into 16 tanks with 30 fish in each tank and fed with four experimental diets. The control group was fed with the basal diet, while the other groups were fed with diets supplemented with 0.1%, 0.2% and 0.3% acidifier, respectively. The results showed that the growth performance of 0.3% group was significantly improved (P0.05) compared with the control group. In addition, the feed coefficient and protein efficiency ratio improved accordingly. Supplementation of acidifier with different concentration in tilapia diets did not significantly affect the moisture, protein, lipid and ash contents of fish body. Hepatosomatic index, intraperitoneal fat ratio,blood concentration of cholesterol, triglyceride, high-density or low-density lipoprotein were not affected, neither. However, the viscerosomatic index of 0.3% group increased significantly compared with the control group (P0.05). The results suggested that supplementation of 0.3% acidifier in diets could significantly improve the growth performance and feed utilization of tilapia, but the fish meat quality was not affected.