Hemorrhagic cystitis (HC) is the syndrome of hematuria combined with symptoms of lower urinary tract irritation in the absence of bacterial infection or generalized hemorrhagic diathesis. HC often occurs as a difficult complication after autologous as well as allogeneic hematopoietic cell transplantation (HCT). It may be secondary to pretransplant preparative regimen (chemotherapy and/or radiation therapy) or viral infection by adenovirus, JC and BK viruses. The most effective treatment for HC has not been established yet. We report a case of a 17-year-old male with common acute lymphoblastic leukemia (cALL) in second CR, who was treated with high-dose chemotherapy (BuCy conditioning regimen) followed by autologous bone marrow transplantation (ABMT), complicated by hemorrhagic cystitis on day 0 (several hours after infusion of transplant material). The immediate use of increased dose of 2-mercaptoethane sulfonate sodium (mesna), bladder irrigation and intensive hydration with forced diuresis resulted in resolution of macroscopic hematuria on day +3 after the transplant and urinary tract recovery with normalization of urine analysis parameters on day +7.