Plantains (Musa paradisiaca L.) are an economically important crop in tropical and sub-tropical regions around the world. Plantains are a staple food in Puerto Rico, they are consumed in many traditional dishes such as mofongo, tostones, and platanutres. Starch is the main component of their carbohydrate content. Plantains, a non-grain starch staple can be used as an ingredient or processing aid in the food industry. Post-harvest preservation is required for plantain crops because of their high perishability and fast deterioration. Extrusion is a pressure-cooking system at high temperatures, which can serve as a fast and versatile method of processing foods into ready-to-eat snacks. This study aimed to develop a ready-to-eat snack based on unripe plantain flour (87.5%) and corn grits (12.5%) using extrusion cooking to offer a new product in the local market. Unripe plantains (ripening stages 1 to 3) from the Maiden cultivar were processed into flour. The extrusion was optimized by response surface methodology (RSM). A single screw laboratory extruder with a compression ratio of 4:1 was used. A central composite rotatable design was used, where the independent variables examined were feed moisture (11% to 15%) and temperature of the barrel central zone (140°C to 160°C). Process variables such as screw speed and die diameter were kept constant at 200 rpm and 3 mm, respectively. The dependent variables examined were expansion ratio, density, shear strength, and shear stress. A sensory evaluation was carried out using a hedonic scale of nine points. The panelists evaluated attributes of general acceptance, texture, and taste. The highest expansion ratio (3.89 ? 0.28) and lowest density (0.211 mg?mm-3 ? 0.03) were obtained at the feed moisture content of 13% and central zone temperature of 150°C. Thus, the product obtained under these conditions had a maximum expansion ratio, an appropriate texture, and good acceptance.