Since the beginning of the 80s, hysteroscopy has proved to be a powerful diagnostic tool for visualizing the cervical canal and the uterine cavity. It yields better results than DandC and it can also be considered an excellent surgical aid in the treatment of endouterine pathologies with the use of the resectoscope. However, the two procedures, diagnostic and operative, have long been considered separate entities, as they required different instruments and a different approach to the patient. Since the introduction at the beginning of the 90s of new scopes with a diameter ranging between 1.2 and 3 mm, it has been possible to produce not only very thin diagnostic sheaths, but also operative sheaths with a diameter less than 5 mm. This has allowed us to perform, simultaneously during the same procedure, diagnosis and treatment of most benign endouterine pathologies without any premedication or anesthesia, reserving the use of the resectoscope and the operative theatre to a few, particular cases. By so doing hysteroscopy has achieved the goal of becoming an outpatient diagnostic and therapeutic procedure that is easily practicable even by beginners, confining resectoscopic procedures for selected cases to be treated by operators with the necessary experience.