Radiation therapy is commonly used to treat pelvic or retroperitoneal cancers but has some impact on genito-urinary system: short-term side effects are frequent with usually a completed regression. However, the incidence of major complications is about 12% and is probably underestimated due to a long delay between radiation therapy and diagnosis of some adverse events such as ureteral strictures or fistula. Clinical follow-up must absolutely include an early diagnosis and treatment of radiation therapy complications such as renal dysfunction, ureteral stricture, ureteral fistula, chronic bladder injury, bladder fistula, urethral stricture, infertility or erectile dysfunction.