In order to analyze the incidence and risk factors for invasive fungal infection (IFI) after allogeneic BMT, 142 consecutive adult BMT recipients (131 sibling donors, 11 unrelated donors) transplanted in 1989-1993 were retrospectively analyzed. There were 21 cases with definite or probable IFI (incidence 15%) (Aspergillus, 15; Candida, four; Fusarium, one; Absidia, one). The median time to the diagnosis of IFI was 136 days after BMT (range 6-466 days). Only 14% of the IFIs were found during the neutropenic period post-BMT. Of the pretransplant characteristics, hematological disease (MDS vs other) (P = 0.001) and unrelated donor (P = 0.01) were risk factors for IFI. Acute GVHD grade III-IV (P = 0.03) and extensive chronic GVHD (P = 0.0002) were also found to be significant risk factors. Only three patients with IFI (14%) became long-term survivors. Invasive fungal infections tended to develop late after BMT, were usually caused by Aspergillus sp., and were strongly associated with GVHD and its treatment. Better prophylaxis and treatment of IFI are needed. More effective prophylaxis for GVHD might decrease the risk of IFI after allogeneic BMT.