purpose: To determine the incidence, risk factors, and outcome of non-Candida fungal infections in a bone marrow transplant population. patients and methods: A consecutive series of 1,186 patients who underwent bone marrow transplant at the University of Minnesota Hospital between 1974 and 1989 were analyzed for the occurrence of a post-transplant non-Candida fungal infection. The risk factors were analyzed with regard to clinical characteristics such as age, sex, primary disease process, type of transplant, recipient cytomegalovirus serostatus, time to engraftment, and the presence of graft-versus-host disease. results: In this population, 123 of 1,186 patients (10%) developed a non-Candida fungal infection within 180 days of transplant. The majority of infections (85%) occurred in allogeneic recipients, and 58% of infections were prior to white blood cell engraftment. The most common isolates were Aspergillus species (70%), Fusarium species (8%), and Alternaria species (5%). Although 47% of infections involved a single organ or site, 44% were disseminated and 9% were isolated fungemias. Only 17% of patients survived. Sixty-eight percent of deaths were related to the fungal infection. In univariate analysis, allogeneic transplant, positive recipient cytomegalovirus serostatus, delayed engraftment, and recipient age of greater than or equal to 18 years were identified as risk factors for non-Candida fungal infection. All of these factors except for recipient age were independently significant in multivariate analysis. In allogeneic recipients, positive cytomegalovirus serostatus, delayed engraftment, and age of greater than or equal to 18 years were each significantly associated with a greater risk of fungal infection; none of these factors were independently significant in the autologous recipients. conclusion: Fungal infections remain a major cause of morbidity and mortality in patients undergoing bone marrow transplant. More effective antifungal prophylaxis and therapy, earlier diagnosis, and transplant regimens incurring a brief period of neutropenia may substantially reduce the incidence and clinical impact of these infections.