Background: Although breast cancer is still the second most common cause of cancer-related deaths, breast cancer mortality has been declining because of advances in the use of adjuvant therapies.; Methods: We summarize clinical trials involving endocrine therapies used to treat early breast cancer and discuss their inception and recent advances.; Results: Endocrine therapies such as tamoxifen have revolutionized the treatment of breast cancer, resulting in significant decreases in cancer-related mortality. Aromatase inhibitors such as anastrozole and letrozole have further improved breast cancer survival.; Conclusion: With the implementation of such therapies resulting in decreased mortality, patients with breast cancer are living longer than ever before. The focus of research is now directed toward the length of treatment and prediction models for recurrence.