The prognosis of patients with malignant brain tumors remains poor despite new developments in neurosurgery, chemotherapy and radiotherapy. Malignant gliomas are highly vascularized, and there is ample evidence that their growth is angiogenesis-dependent. Therefore, new therapeutic approaches often include the inhibition of angiogenesis. In this review, experimental studies of antiangiogenic agents in brain tumor models are summarized. The results of these experiments as well as potential pitfalls in extrapolation to the clinic are discussed.