Invasive fungal infections (IFIs) are a common problem in immunocompromised patients. Patients with leukemia, especially those undergoing stem cell transplantation, are at increased risk for IFIs, particularly invasive aspergillosis (IA). Serial monitoring with the recently approved Aspergillus galactomannan antigen test has helped to improve the diagnosis and the monitoring of treatment of IA in cancer patients. There are several new options to treat cancer patients with fungal infections. These include new antifungal agents, such as the mould-active triazoles (itraconazole, voriconazole, and posaconazole), the echinocandins (anidulafungin, caspofungin and micafungin), and the lipid formulations of amphotericin B. Immunotherapy with hematopoietic growth factors and interferon-gamma has been effective in some patients. Finally, donor-stimulated granulocyte transfusions may be useful in this patient population, but further research is required.