There is a rising incidence of brain metastases from breast cancer. Having an improved means of detecting and monitoring such brain metastases would be valuable. Using samples stored in our Cerebrospinal Fluid (CSF) Bank, we identified 176 samples from 71 patients with brain metastases from breast cancer. The CSF VEGF levels were measured using enzyme-linked immunosorbent assay and normalized to phosphate buffered saline. The highest CSF VEGF ratios from individual patients were correlated with patient survival. The median CSF VEGF ratio was 1.043, with a range of 0.575 to 22.060. At the time of analysis, 51 patients were deceased while 30 were alive, with a median survival of 4 months. The median survival of patients with CSF VEGF ratio ≤ 1.000 was 7 months (range 1 to 31 months) versus 2.5 months (range 0.5 to 60 months) for those with CSF VEGF > 1.000. Furthermore, increasing CSF VEGF levels also appear to correlate with increasing number of brain metastases detected on magnetic resonance imaging. We conclude that VEGF is a potential biomarker in the CSF for brain metastases from breast cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1456.