The broad spectrum antifungal itraconazole is an effective and well tolerated agent for the prophylaxis and treatment of systemic fungal infections. The recent development of an itraconazole oral solution and an intravenous itraconazole solution has increased the options for the use of this drug and increased the oral bioavailability in a variety of at-risk patients. Reliable absorption of the itraconazole oral solution has been demonstrated in patients with HIV infection, neutropenic patients with haematological malignancy, bone marrow transplant recipients and neutropenic children. In clinical trials, itraconazole oral solution (5 mg/kg/day) was more effective at preventing systemic fungal infection in patients with haematological malignancy than placebo, fluconazole suspension (100 mg/day) or oral amphotericin-B (2 g/kg/day) and was highly effective at preventing fungal infections in liver transplant recipients. There were no unexpected adverse events with the itraconazole oral solution in any of these trials. In addition, intravenous itraconazole solution is at least as effective as intravenous amphotericin-B in the empirical treatment of neutropenic patients with systemic fungal infections, and drug-related adverse events are more frequent in patients treated with amphotericin-B. A large proportion of patients with confirmed aspergillosis also respond to treatment with intravenous itraconazole followed by oral itraconazole. The new formulations of itraconazole are therefore effective agents for prophylaxis and treatment of most systemic fungal infections in patients with haematological malignancy.