Estrogen plays a key role in the physiology of the vagina. The multi-layering of the vaginal epithelium is regulated by estrogen, as well as the function of the cervical glands, connective trophism, vascularization and the local immune system itself. All conditions of hypoestrogenism, be they physiological such as menopause, the menopausal transition period, the puerperium and jatrogens as treatments for estrogen dependent diseases, but also the use of hormonal contraceptives containing only progestin or low doses of ethinylestradiol are risk factors for atrophy of vagina and urinary tract, which is also modulated by estrogen. In all conditions of hypoestrogenism, detectable by a correct medical history, the Gynecologist must ask specific questions about the specific symptoms both in the fertile age and after the menopause, focusing on the genitourinary syndrome. A careful examination must make a differential diagnosis with dermatological or autoimmune diseases, and evaluate the intensity of the problem with internationally validated scales. Once the diagnosis has been established and contraindications to the use of estrogen have been excluded, the first-line treatment is the use of vaginal estrogens, such as estriol, estradiol or promestriene and conjugated estrogens. The proposed treatment must be monitored at regular intervals to assess its effectiveness, safety and acceptability.