Breast cancer continues to be the second-leading cause of cancer in world. Early detection, improved surgical techniques, and more effective therapy methods have improved quality of life and survival for patients, particularly those with less advanced diseases. Therefore, tremendous amounts of time and efforts are dedicated to search toward earlier detection and more efficient treatment of breast cancer. Advances in molecular cancer biology achieved an increased understanding of the biologic factors that contribute to breast cancer pathogenesis and progression. This understanding has already led to more effective treatment. Among different therapy modalities, nuclear medicine provides an important role to the clinical management of breast cancer. In this review, the history of radioimmunotherapy of breast cancer as a targeted molecular method is reviewed.