Research covers course of thrombocytopenia in HIV-infected children with different speed of progress of disease. The goal of the research is making recommendations on optimization of their treatment. 207 children with perinatally transmited HIV-infection were included to the study. In the probed cohort thrombocytopenia was the frequent haematological manifestation of HIV infection and observed in 25.12 % cases. Development of thrombocytopenia during the first year of life at HIV-infected children testifies to the high risk of rapid progression of HIV-infection.