OBJECTIVES: Breast cancer (BC) is the second neoplasm which disseminates brain metastases (BM). We estimated the incidence of patients with BCBM, those over-expressing HER2 (HER2+), and the costs related to their management using the new chaining system of the French hospital information program (PMSI). This was to identify predictors of costs. METHODS: A retrospective analysis using the PMSI database (2006-2008) was conducted to estimate the number of public and private stays related to the diagnosis of BCBM. Stays were extracted and chained to patients’ identification number to calculate the number of patients concerned by BCBM. The administration of trastuzumab was used as a surrogate for the HER2 status. Costs were estimated from the health insurance perspective including health-related group tariff, supplements for intensive care, number and length of stays, expensive-drugs status. Spearman’s rank correlation coefficient and nonparametric test (Kruskal-Wallis) were used for univariate analyses. RESULTS: In 2008, 3610 women were hospitalized for BCBM (vs. 3273 and 3523 in 2006 and 2007 respectively) of whom average age was 56.1 years (SD: 13.3).  Patients had an average of 4.8 hospitalizations (SD: 6.4) mostly for palliative care (42%), chemotherapy (39%) and radiotherapy (14%). Twenty-one percent of patients suffered from BM only and 79% had multiple metastases; 16% were identified as HER2+. Annual mean cost of care was €8,049 per patient with BCBM compared with €19,412 specifically for HER2+ patients (respectively, 11% and 59% were dedicated to expensive-drugs). Age (p<0.001), patients with newly diagnosed BCBM (p<0.001), and the number of metastases (p<0.001) were associated with the cost of BCBM. CONCLUSIONS: Incidence of BCBM seemed to increase during 2006-2008. BCBM management appeared resource-consuming especially for HER2+ patients. The development of chaining system in PMSI database is an opportunity to estimate economic data accurately as well as to generate epidemiological data from an exhaustive database.