A single-factor experiment was conducted to study the influence of process variables on the degree of texturization (DTE) by a twin-screw extruder. By using response surface methodology (RSM), the feed rate, feed moisture, screw speed-1-1 and extrusion temperature were optimized at 35r min , 30%, 175r min , and 145 ºC, respectively. The observations on tensile force and final protein content (after immersion in water) of the extrudates were studied. The data of this study suggest that fish and soybean protein concentrate extruded by twin screw extruder would be of great interest to the researchers. Degree of texturization, Extrusion parameter, Fish muscle-soy protein, Twin-screw extruder Under the optimum conditions, the characteristics of the extrudate including the degree of texturization, tensile force, protein content, fat content, and in vitro digestibility of the extrudate were at 2.12, 3224.6g, 67.9%, 1.56%, and87.4%, respectively. The texturized extrudate shows a great prospect by providing value-added high protein product. Effect of extrusion variables on the extrudate characteristics of fish muscle-soy protein blend and optimization of these variables