Four hemodialysis patients receiving deferoxamine for metal overload had fatal rhinocerebral rhizopus infections. Serious fungal infections are not commonly seen in patients on dialysis, and none of these patients had the usual risk factors for rhizopus infection. Deferoxamine is being used with increased frequency in dialysis patients for aluminum and iron overload states. We propose that there is a link between the deferoxamine therapy and this unusual infection. Deferoxamine may serve as a specific growth factor for Rhizopus species or may alter host immune function. We suggest searching for fungal organisms in patients with unexplained illnesses receiving deferoxamine.