Background: Breast cancer is the most common cancer among women and comprises 26% of all cancers diagnosed in women in the United States. Among presenting patients, 3 - 6% already have metastatic disease, and 50 - 70% of the remaining patients develop systemic relapse. Recently many new drugs, particularly molecular targeted therapies, have been developed in the field. Objective: To review the current and emerging data on the treatment of metastatic breast cancer, with emphasis on novel therapies that show promise. Methods: PubMed and ASCO annual meeting abstracts were used for a literature search. Results/conclusions: Despite improved response rates, conventional treatments still result only in transient remission in most cases. New therapeutic alternatives and new strategies to overcome drug resistance are needed to improve these results.