Background: Since the introduction of trastuzumab into the treatment of Her-2/neu-positive metastatic breast cancer, cases of long-term survival have become more frequent. Even after tumor progression, trastuzumab seems to retain its antitumor activity which is potentiated by the combination with a chemotherapeutic agent. Case Report: We are reporting about the unusual clinical course of a young patient with Her-2/neu-positive breast cancer, who experienced progression of pulmonary and bone metastases under treatment with trastuzumab. Upon progression, a combination therapy with capecitabine/trastuzumab was initiated, and a partial remission was achieved which has continued for over 4 years. Conclusion: This unusual clinical course shows that continuing trastuzumab-based therapy beyond progression is a safe, effective, and well-tolerated option which can induce long-term remissions in some patients with Her-2/neu-positive metastatic breast cancer.