Malignant gliomas have long been a therapeutic dilemma in neuro-oncology, with a poor overall prognosis. Standard treatment, consisting of primary resection, followed by radiation therapy and temozolomide, has improved prognosis. Recently, studies have looked at the addition of bevacizumab (Avastin), a humanized murine IgG1 monoclonal antibody against vascular endothelial growth factor-A, to conventional regiments. Bevacizumab gained US FDA approval for single agent use in recurrent glioblastoma in 2009. Known side effects of bevacizumab include increased risk of arterial and venous thromboembolism, as well as hemorrhage. With emerging data for the use of bevacizumab in malignant gliomas, the extent of risks such as bleeding and thrombosis in patients with primary brain tumors treated with bevacizumab remains unknown. Here, we present only the second reported case of dural venous sinus thrombosis during treatment with bevacizumab and the first reported case for a primary glioma treated with temozolomide, radiation, and bevacizumab.