We describe a case of mixed Rhizopus oryzae and Aspergillus niger infection in a 38 year-old woman who had undergone allogeneic bone marrow transplantation for multiple myeloma. The fungi were isolated from a necrotic ulcer under a plaster cast stabilizing a pathological fracture of the left humerus. We emphasize the necessity for frequent inspection of any covered area of skin and the use of sterile dressings as far as possible in neutropenic patients.