Hematopoietic stem cell transplantation (HCT) in patients with prior or active invasive aspergillosis (IA) is a frequent consideration. We reviewed outcomes of 2319 patients who underwent transplantation between 1992 and 2001 in our institution, among whom 45 patients (1.9%) had a known history of IA before HCT. Posttransplantation IA occurred in 13 of these 45 patients with a pretransplantation history (29%). Nine infections were considered recurrent by anatomic site and timing. Compared with all other patients who received allogeneic HCT during the same period, patients with histories of IA had lower overall survival (56% versus 77%; P =.0001) and higher transplant-related mortality (TRM; 38% versus 21%; P =.0001) 100 days after HCT, associated mainly with IA and other pulmonary complications. Among patients with prior IA, posttransplantation IA occurred more frequently in patients who received <1 month of antifungal therapy before HCT (4/6 versus 6/39; P =.001). The probability of posttransplantation IA and overall survival among patients who received >1 month of antifungal therapy and had resolution of radiographic abnormalities were not different from those of patients without prior IA. Patients with prior IA who received conditioning with total body irradiation (TBI) had higher TRM compared with those who received nonmyeloablative and non-total body irradiation-based regimens (16/31 versus 2/14; P =.024). Thus, the duration of antifungal therapy before transplantation, the resolution of radiographic abnormalities, and conditioning regimens are important variables to consider for minimizing the risk for IA recurrence and TRM after allogeneic HCT.