A model for the study of tumor angiogenesis within the rabbit brain is presented. Implantation of the VX2 carcinoma provides a reproducible tumor accompanied by angiogenesis. The authors report the sequential growth, histology, tumor neovascularization, and vascular permeability of this tumor following its intracerebral implantation. Tumor angiogenesis correlates with the rapid and logarithmic intracerebral tumor growth. The proliferation of blood vessels in the tumor and the organization of tumor cells around tumor vessels are described. Breakdown of the blood-brain barrier (detected by Evans blue leakage) starts in the early stages of tumor development and becomes prominent as the tumor vasculature and size increase. This model is useful for experimental studies of angiogenesis.