BACKGROUND: There is no sufficient evidence to establish a standard of care for patients with brain metastases (BM) from HER2(+) breast cancer (BC). The aim of this study was to assess the impact of local and systemic treatments on the outcome of patients diagnosed with BM from HER2(+) BC over a period of 10 years, from 2005 to 2014. PATIENTS AND METHODS: Data of 154 patients were retrospectively collected at 14 Italian institutions through a specifically designed database. RESULTS: Median overall survival (OS) was 24.5 months. Patients receiving surgery/stereotactic radiosurgery experienced longer OS compared to those receiving whole-brain radiotherapy or no treatment (33.5 vs. 11.4 months; hazard ratio = 0.34; 95% confidence interval, 0.22-0.52; P <.001). Interestingly, whole-brain radiotherapy did not improve OS compared to no treatment (11.4 vs. 9.8 months; hazard ratio = 0.99; 95% confidence interval, 0.62-1.62; P = .99). HER2-targeted therapy was associated with better OS compared to systemic therapy without HER2-targeted therapy or no systemic therapy (27.5 vs. 5.4 months; hazard ratio = 0.26; 95% confidence interval, 0.17-0.41; P <.001). At multivariate analysis stratified by local treatments, systemic therapy, Karnofsky performance status, and neurologic symptoms significantly affected OS. Age, number of BM, steroid therapy, number of previous lines of systemic therapy, status of extracranial disease, and period of diagnosis had no significant impact on OS. CONCLUSION: Patients with BM from HER2(+) BC treated with surgery/stereotactic radiosurgery as local treatment and HER2-targeted therapy as systemic treatment experienced the best outcomes. Patients with low Karnofsky performance status and neurologic symptoms had poor survival.