Alkaline proteases from the red scorpionfish (Scorpaena scrofa) viscera were extracted and characterized. This pro-teolytic crude extract was active and stable in alkaline solution: it was extremely stable in the pH range of 5.0–12.0;the optimum pH and temperature were 10.0 and 55◦C, respectively, using casein as a substrate. Three caseinolyticproteases clear bands were observed in the zymogram test suggesting the presence of at least three different major proteinases.