This study was carried out on 70 patients with haematological or solid malignancies who were receiving chemotherapy and/or radiotherapy. Forty-one patients were randomly assigned to receive fluconazole, 400 mg/day, while they were neutropenic. Systemic fungal infection developed in four of the 41 patients (9%) receiving prophylaxis in comparison to nine of 29 patients (31%) not receiving prophylaxis. The incidence of systemic fungal infection was significantly different between the groups receiving prophylaxis and those not receiving it (p < 0.05). Fluconazole was found to be effective for preventing systemic fungal infections in neutropenic patients with cancer.