As a frequent endourological procedure, transurethral resection of bladder tumors (TURB) represents a major field of activity for urological surgeons. Although TURB represents an endoscopic training procedure for urology residents, there are clear requirements for the quality of the surgical procedure as such. The knowledge of possible complications and their management are essential for urologists active in the clinical field. Bleeding complications, bladder perforation, infections and injuries to the ureteral orifice are the most frequently observed complications. This article summarizes the essential risks and complications as well as the corresponding preventive and therapeutic measures.