Acute graft-versus-host disease (GVHD) is a common complication of allogeneic hematopoietic stem cell transplantation (HSCT). It has been proposed that tumor necrosis factor alpha (TNF-alpha) blockade with infliximab may be an effective treatment for severe (grades III-IV) GVHD. We determined if infliximab use in this high-risk population was associated with an additional increased risk of non-Candida invasive fungal infections (IFIs). Records of the 2000-2001 HSCT cohort at our institution were reviewed. Fifty-three (20%) of 264 evaluable patients developed severe GVHD and 11 of these 53 (21%) received infliximab for treatment. Proven or probable IFI was documented in 10 (19%) of 53 patients with severe GVHD (incidence rate of 0.99 cases/1000 GVHD patient-days). When stratified by infliximab use, 5 of 11 infliximab recipients developed an IFI (6.78 cases/1000 GVHD patient-days), compared with 5 of 42 IFI cases among nonrecipients (0.53 cases/1000 GVHD patient-days). In a time-dependent Cox regression model among patients with severe GVHD, the adjusted IFI hazard ratio of infliximab exposure was 13.6 (P =.004; 95% CI, 2.29-80.2). We conclude that infliximab administration is associated with a significantly increased risk of non-Candida IFI in HSCT recipients with severe GVHD disease. Pre-emptive systemic antifungal therapy against molds should be considered in patients who develop severe GVHD after HSCT if infliximab is used.