Breast cancer and ovarian cancer are closely related. The major common risk factors of these 2 types of cancer are likely genetic factors. However, few studies have shown any common characteristics in patients who have both types of these 2 cancers. The purpose of this retrospective study is to explore the clinical characteristics and survival outcomes of patients with both primary breast cancer and primary ovarian cancer.A cohort of patients who had a history of both primary breast cancer and primary ovarian cancer were enrolled, and they received treatment in the Peking Union Medical College Hospital between January 1, 2010, and December 31, 2018. Both descriptive statistics analysis and survival analysis were performed for analysis.A total of 114 patients with both primary breast cancer and primary ovarian cancer were included in the study. The median (range) follow-up was 129.5 (20-492) months. The average interval time between the diagnosis of 2 types of cancer was 79.4 months in patients having ovarian cancer firstly and was 115.9 months in patients having breast cancer firstly. The 5- and 10-year overall survival (OS) rates were 91.5% and 81.7% for patients with ovarian cancer following breast cancer, respectively, and 90.6% and 87.5% for patients with breast cancer following ovarian cancer, respectively. Multivariate analysis revealed that independent predictors of OS were the age of diagnosis of the first tumor and the time interval between two types of tumor in patients with ovarian cancer following breast cancer.Most breast cancer or ovarian cancer occurred within 5 years after being diagnosed with the first tumor, and the interval time was significantly shorter in patients with previous ovarian cancer. The prognosis is likely positively correlated to the interval time between the occurrences of two types of cancer.