Classification and nomenclature of proteolytic enzymes (peptidases) and their biochemical properties are described. Peptidases catalyze hydrolysis of peptide bonds in proteins and thus significantly affect nutritional, sensoric and textural properties of food proteins in raw materials, intermediates and end products. They found application in pharmacological research as well as in washing powders, textile and leather industry, cosmetics, etc. Good knowledge of their properties, as well as their optimal processing parameters and enzyme specificity are essential for their successful applications both in research and industry.