OBJECTIVE Study species composition and factors of pathogenicity of staphylococci isolated from intestine biotope of children with HIV-infection. METHODS 75 strains of staphylococci from HIV-positive and 45 strains from HIV-negatfive children were isolated and identified. Factors of specific adhesion, colonization potential, invasion factors and toxin-formation of staphylococci were studied. RESULTS In HIV-infected children Staphylococcus aureus, Staphylococcus xylosus, Staphylococcus epidermidis dominated. Quantitative level of S. aureus was 1.8 x 10(7) PFU/g. Adhesion, production of hemolysin, DNAse did not differ from the comparison group (p > 0.05). Lipase activity in staphylococci from HIV-infected children was higher than in the control group (p < 0.05). CONCLUSIONS The data obtained reveal some mechanisms of development of endogenous infection in HIV-infected children.