Morphological-cultural and physiological-biochemical properties of 24 strains of microorganisms agents of pyo-inflammatory complications of different localization in patients with hemophilia have been studied. Microorganisms strains presented by the following species: Staphylococcus aureus, S. epidermidis, S. saprophyticus, Proteus vulgaris, P. morganii, Hafnia alvei, Serratia marcescens, have been identified. It was found out that in monoculture staphylococci prove to be the leading etiological agent (60.9%), gram-negative enterobacteria (52.2%) and bacterial associations (8.7%) occur more rarely. Special attention was paid to the study of resistance of antibiotics, circulation and pathogenicity factors that had a direct effect on the main disease severity. It was ascertained that high activity of enzymes and presence of pathogenicity factors were the peculiarities of microorganisms isolated from pyo-septic sites in patients with hemophilia. All the strains possessed multiple resistance to antibiotics.