The risk of invasive aspergillosis (IA) is considered to be low among autologous HSCT recipients, but an increase in the incidence has been observed recently in this setting. The aim of the study was to assess the influence of immunosuppressive drugs (steroids, rituximab, fludarabine, thalidomide), used in treatment of lymphoid malignancies during 6 months of pretransplant period, on IA incidence after autologous HSCT. A total of 109 patients with non-Hodgkin's lymphoma (NHL), Hodgkin's disease (HD) and multiple myeloma (MM), conditioned with carmustine, etoposide, cytarabine, melphalan or melphalan and transplanted with PBSC, were analyzed prospectively. Patients were monitored with twice-weekly galactomannan test. High-resolution computed tomograhy of the chest and bronchoscopy were performed in case of positive galactomanan test, persistent fever or pulmonary infiltrates. Documented IA was diagnosed in nine (8%) patients (three proven, six probable). The incidence of IA was comparable in NHL, HD and MM patients and not influenced by age, advanced disease or conditioning regimen. Factors significant for development of documented IA by univariate analysis were treatment with fludarabine (P=0.008) or rituximab (P=0.039). The only factor predicting documented IA by multivariate analysis was treatment with fludarabine (P=0.008). Patients treated with fludarabine or rituximab in pretransplant period are at risk of IA and require close monitoring and/or anti-mould prophylaxis.