Studies to design a dry chromogenic nutrient medium for the diferentiation of Klebsiella were under way, by detecting the intracellular Klebsiella genus-specific enzyme of human potential pathogenicity--5-aminosalicylate decarboxylase. The composition of the proposed medium that ensured its high sensitivity and improved its differentiating properties as compared with the known traditional media was worked through. Klebsiella are isolated and identified on the proposed medium in one step, which substantially reduces diagnosis time and material costs and takes some burden from microbiologists.