Fluconazole antifungal prophylaxis is standard care in allogeneic hematopoietic stem cell transplant (HSCT) recipients, but this drug lacks anti-Aspergillus activity, the primary cause of invasive fungal infection (IFI) in many transplantation centers. We performed a randomized trial to compare itraconazole vs fluconazole, for prevention of IFIs in patients with acute leukemia (AL) and HSCT recipients. One hundred and ninety-five patients were randomly assigned to either fluconazole or itraconazole antifungal prophylaxis, after stratification into high-risk and low-risk groups. Antifungal prophylaxis was started at the beginning of chemotherapy and continued until resolution of neutropenia, or until amphotericin B treatment was started. IFI occurred in 11 (11%) of itraconazole, and in 12 (12%) fluconazole recipients. Invasive candidiasis (IC) developed in two (2%) itraconazole and one (1%) fluconazole recipients, while invasive aspergillosis (IA) developed in nine (9%) itraconazole and 11(11%) fluconazole recipients. There was no difference in the incidence of total IFI, IC and IA between the two study arms. However, there was a nonsignificant trend towards reduced mortality among patients who developed IA while receiving itraconazole prophylaxis (3/9=33% vs 8/11=73%, P=0.095).