Summary:We describe the successful treatment of a 20-year-old patient with chronic granulomatous disease (CGD), by unrelated bone marrow transplantation (UBMT). The patient is relatively old compared to other CGD patients treated with BMT. He had had repeated serious infections from early childhood and was diagnosed as CGD, gp91-phox deficiency. Prolonged antibiotic-resistant pneumonitis worsened when the patient was 18 years old. In addition, he suffered Aspergillus osteomyelitis and acute renal failure due to amphotericin B. He received 94 granulocyte transfusions from 94 adult donors and the infections gradually improved. In September 1998, at 20 years of age, he underwent UBMT from an HLA 6 antigen-matched male donor, with CY and TBI conditioning. He received MTX and CsA as prophylaxis against GVHD. No serious complications occurred and rapid engraftment was achieved. Acute GVHD (grade 2, at day 19) and chronic GVHD (limited, at day 192) occurred. However, both were easily controlled. The patient is alive and well with no late rejection 26 months after UBMT. Bone Marrow Transplantation (2001) 28, 83-87. Keywords: chronic granulomatous disease; unrelated bone marrow transplantation; aspergillosis; granulocyte transfusions Chronic granulomatous disease (CGD) is a primary immunodeficiency disease characterized by recurrent severe bacterial and fungal infections during early childhood. CGD is caused by dysfunctional phagocytosis that is a result of defective NADPH oxidase. Deficiency of this oxidase causes a marked reduction in the phagocyte respiratory burst resulting in defective microbial killing. IFN-␥, supportive therapy and prophylactic administration of therapeutic agents such as sulfamethoxazole-trimethoprim have improved the prognosis.