Breast cancer is considered one of the most common neoplasms worldwide. Diabetes (DM) increases mortality among postmenopausal patients with breast cancer. Our study aims to identify the risk factors of DM-specific mortality and infiltrating ductal carcinoma (IDC) mortality in patients with IDC of the breast. Data of IDC patients were obtained from the Surveillance, Epidemiology, and End Results database from 1975 to 2016. Independent variables included age, race, marital status, the primary site of IDC, breast subtype, the disease stage, grade, chemotherapy, radiation, and surgery. Kaplan-Meier, Cox and Binary regression tests were used to analyze the data using SPSS software. A total of 673 533 IDC patients were analyzed. Of them, 4224 died due to DM and 116 822 died due to IDC. Factors that increase the risk of overall, IDC-specific, and DM-specific mortalities include older age, black race, widowed, uninsured, regional and distant stages, grade II and III, and no treatment with chemotherapy or radiotherapy or surgery. Additionally, the IDC mortality increased with separated status, all primary sites, all breast subtypes, and stage IV. In patients with IDC, controlling DM besides cancer is recommended to reduce the mortality risk. Old, black, widowed, uninsured, regional and distant stages, grade II and III, and no treatment are common risk factors for DM- and IDC-mortality.