Background: Breast cancer is the most common malignancy in women in US and the second cause of cancer death. It comprises 14 % of all new cancers, and 6.8 % of all cancers deaths. Objectives: To evaluate the value of targeted therapy (trastuzumab) in HER-2 positive metastatic breast cancer patients previously treated with anthracycline in the adjuvant setting, in terms of related toxicities, objective response, overall survival, and progression free survival. Patients and Methods: This study included 80 patients with history of primary carcinoma of the breast with HER2neu positive and evidence of metastases. Half the cases received a combination of trastuzumab plus paclitaxel aiming to treat their disease compared with other group, which received paclitaxel alone to asses the effect of trastuzumab. Results: Adding trastuzumab to paclitaxel showed significant positive impact on treatment, objective response, progression-free survival (PFS) and overall survival (OS). In the attempt to evaluate the variable prognostic importance, such as positive family history, performance status, disease grade and tumor size all showed significant impact on objective response, PFS and OS. Conclusion: The metastatic form of the breast cancer is of dismal prognosis. Targeted therapy created a new avenue in the management of this grim disease. This study show that adding trastuzumab to paclitaxel had significantly improved the objective response, PFS and OS.