In order to increase the efficiency of lysotyping as a method for differentiating Klebsiella strains the authors tested the activity of 10 additional phages isolated, prepared and studied in the laboratory and compared to the Slopek-Milch set. A number of 734 Klebsiella strains were isolated in different clinical and epidemiological conditions and lysotyped. The phage type was determined in 64.60% of the strains examined, using 15 phages of the Slopek-Milch set. By using additional autochtonous phages the proportion of lysotypable strains reached 77.80%; therefore, 13.20% were sensitive only to the additional phages.