In this study, the effects of Rutin on the isolated urinary bladder smooth muscle contractions and bladder histopathology in Cyclophosphamide (CP)-induced hemorrhagic cystitis in rats were investigated. In study, twenty-four adult female Sprague Dawley rats were used and the avarage weight of the rats was 200-250 g. Four experimental groups were formed and each group had 6 rats. The control and CP groups were administrated intraperitoneally (ip) physiologic saline solution for 7 days. Also, CP group was injected the single dose of CP (150 mg/kg, ip) on the fifth day of saline administration. The Rutin application groups, Rutin (50 mg/kg, ip) dissolved in physiological saline were injected for 7 days. The Rutin+CP group was administered a single dose of CP on the fifth day of Rutin administration. On the 8th day of the experimental procedure, the rats were decapitated in the presence of anesthesia and their bladders were isolated. The contraction values induced by Acetylcholine (ACh) (10-4 M) and Potassium Chloride (KCI) (60 mM) in isolated bladder smooth muscle strips were obtained. Besides, urinary bladders were performed the histopathologic evaluation by staining with hematoxylin eosin. It was determined that the increased in vitro contractions induced by ACh and KCl in the CP group rats but not statistically significant (P>0.05) and Rutin administration was reduced the increased contraction responses. Histopathological examination was seen that Rutin reduced these changes while epithelial rash in the bladder lumen, desquamation in the mucosal epithelium, coagulation necrosis and severe erythrocyte. In conclusion, in CP-induced hemorrhagic cystitis was determined to be a protective effect of Rutin application on bladder contractility and histopathology.