Abstract: The objective of this experiment was to determine the effects of methionine (DLM) , 2 - hydroxy - 4 - (methylthio) butanoic acid (HMTBA) on muscle protein synthesis and flesh texture in broiler chickens. 105 male Ross broiler chickens (49g) were randomly divided into 7 groups (15 birds per group) , with 3 replicate pens per treatment and 5 birds per pen. All broilers were offered the same basal diet with added DLM and HMTBA at levels of 0 (control group) , 0. 1% and 0. 3% (starter phase) , 0. 08% and 0. 24% (finishing phases) . Results:The body weight gain, leg weight and leg muscle rate were significantly higher in 0. 3% HMTBA group (p<0. 05) , as compared to the control group. Additionally, a significant increase of RNA content, protein content and CS ratio were found in 0. 1% DLM, 0. 1% HMTBA and 0. 3% HMTBA groups (p<0. 05) . Moreover, broiler chickens fed with 0. 3% HMTBA had a significant lower glucose and higher glycogen content and ATPase activity in muscle as compared to the DLM group and control group. A significant decreased hardness, gumminess, and chewiness of flesh were also indicated for 0. 3% HMTBA group. Conclusion:Compared with DLM, HMTBA could better enhance protein synthesis, accelerate muscle growth, and improve flesh quality in broiler chickens.