Breast cancer is one of the most commonly diagnosed malignancies and is the main cause of death in women aged 40-49 years. Metastatic breast cancer is a heterogeneous disease that has a variety of different clinical presentations, ranging from solitary metastatic lesion to diffuse and multiple organ involvement. The biological heterogeneity of metastatic breast cancer has led to its unpredictable clinical behavior. One of the major challenges, therefore, is to identify predictive and prognostic models facilitating the selection of patients who can benefit from more aggressive and potentially curative options. This article provides an overview of the current management of metastatic breast cancer with focused emphasis on radioimmunotherapy.