Studying of cytologic preparations of bone marrow doesn’t yield decisive results for diagnosis of hypoplastic anemia. Even at considerable devastation of bone marrow the needle can get to the center of the remained myelogenesis. It creates wrong idea of sufficient blood formation. At suspicion on bone marrow hypoplasia in connection with panhematopenia in peripheral blood it is necessary to apply core biopsy. This method gives an idea of replacement extent of bone marrow with fatty tissue. In cytologic preparations of marrow at hypoplastic anemia it is possible to reveal some features.