To provide information including the trend of gynecological malignancies in Japan, we hereby present the annual patient report for 2020 and the Annual Treatment Report for 2015, on the outcomes of patients who started treatment in 2015. The Japan Society of Obstetrics and Gynecology maintains an annual tumor registry, where information on gynecological malignancies from various participating institutions is gathered. The data of patients whose treatment with gynecologic malignancies was initiated in 2020 were analyzed retrospectively. Survival of the patients who started treatment with cervical, endometrial, and ovarian cancer in 2015 was analyzed by using the Kaplan-Meier, log-rank, and Wilcoxson tests. Treatment was initiated in 2020 for 7689 patients with cervical cancer, 13 113 with endometrial cancer, 8004 with ovarian, tubal, and peritoneal cancer, 2152 with ovarian borderline tumors, and with the others (260 vulvar cancer, 157 vaginal cancer, 464 uterine sarcoma, 50 uterine adenosarcoma, 136 trophoblastic diseases). This clinicopathological information was summarized as the patient annual report. The 5-year survival rates of the patients with cervical cancer were 92.3%, 76.2%, 56.5%, and 32.2% for Stages I, II, III, and IV, respectively. The 5-year survival rates for the patients with endometrial cancer were 93.9%, 87.6%, 71.4%, and 29.3% for Stages I, II, III, and IV, respectively. The 5-year survival rates for the patients with ovarian cancer (surface epithelial-stromal tumors) were 91.7%, 80.6%, 50.8%, and 39.7% for Stages I, II, III, and IV, respectively. The annual tumor report is an important survey that provides knowledge on gynecological malignancy trends in Japan.