Prevalence rates of major depressive disorder (MDD) following breast cancer diagnosis are estimated to be ~5% to >20%, and these rates range from slightly below to somewhat above the expected prevalence rate for MDD in the general population of women in the United States. Women with a history of MDD are at increased risk for recurrence of MDD after breast cancer and need to be monitored closely. To properly diagnose and treat MDD, healthcare providers must be able to recognize depressive symptoms and distinguish them from similar somatic symptoms that are associated with breast cancer and breast cancer treatment. The National Comprehensive Cancer Network and the American Society of Clinical Oncology have published guidelines for the screening, assessment, and care of adult cancer patients with depressive symptoms. Use of a standardized and validated screening measure may help healthcare providers identify patients in need of further assessment or treatment. Evidence-based nonpharmacological interventions such as cognitive behavioral therapy and antidepressant medications are recommended treatment options.