The vaginal response to estriol succinate was studied in 40 oncogynecological patients, 20 with irradiation (study group) and 20 without irradiation (control group). Both groups had artificial established menopause at the beginning of the treatment. The previous clinical and cytological patterns to estrogen therapy were more severe in the irradiated group; they presented the highest degree of vaginal atrophy which was related to the type and therapeutic dose used. Response of the study group to a continuous 4 mg of estriol as well as the control group, both has a positive effect in vaginal cytology and alleviates postmenopausal symptoms and improve the quality of life.