We report the clinical course of a patient who developed a Rhizopus infection of his right lung and pleural cavity, 11 months after receiving a T-cell-depleted, haploidentical donor peripheral blood stem cell transplant. Thoracotomy was performed to remove the pulmonary lesion, but residual disease in the pleural cavity was noted. Treatment with amphotericin B was complicated by the development of severe renal dysfunction, necessitating alternative antifungal therapy. Treatment was initiated with the investigational triazole posaconazole. Despite concurrent treatment with corticosteroids for graft-versus-host disease (GVHD), the patient had a complete response and remains well 4 years later.