We analyzed the success of suprapubic cystotomy in patients with severe hemorrhagic cystitis after bone marrow transplantation. Seventy-three out of 963 patients developed severe hemorrhagic cystitis which resulted in urinary tract obstruction after high-dose cytoreductive therapy. Eleven patients (15%) failed medical treatment and required emergency suprapubic cystotomy. Three of these patients died of other complications prior to resolution of HC. Of the remaining 8 patients who underwent surgery, 4 are alive. The mortality rate was significantly higher in patients who required surgery than in those who responded to medical therapy. Patients whose HC required surgery also had a greater transfusion requirement than those who responded to medical therapy. We conclude that surgical treatment of severe HC should be undertaken only after failure of medical therapy.