The authors estimated the incidence of mycotic infections among children patients with histological diagnosis of solid tumors during the period of neutropenia. Superficial mycoses including mucoses were observed in 35.3% of analysed patients, while a disseminated mycotic infections of a severe clinical course were seen in 2.9% neutropenic patients. Prophylactic administration of Diflucan (1-2 mg/kg/24h)(fluconazole) in neutropenic patients proved efficient in great majority of children, preventing the occurrence of severe mycotic complications.