The clinical efficacy and the safety of fluconazole as given at an intravenous dose of 100-400 mg daily were assessed in 7 patients with deep mycosis associated with hematological malignancy. Enrolled in the study were 1 patient with acute lymphatic leukemia, 1 with acute myelocytic leukemia, 2 with acute myelomonocytic leukemia, 2 with malignant lymphoma and 1 with myelodysplastic syndrome. Pathogens isolated from 4 patients were all Candida species including 2 Candida albicans, 1 Candida parapsilosis and 1 Candida krusei. Diagnoses of fungal infections of the patients were Candida pneumonia in 3 patients, candidemia in 1 and fungemia suggested in 3. Assessment of the clinical efficacy was made on 4 patients from whom pathogens were isolated. The global clinical improvement was good in 2 patients and fair in 1 with Candida pneumonia and good in 1 with candidemia. In the mycological assessment, pathogenic fungi were eradicated in 3 patients and decreased in 1 patient. No significant adverse reactions nor abnormality in clinical laboratory tests related with the dosing of fluconazole were observed in any of the patients.