Angiogenesis, the development and proliferation of new blood vessels, is critical for the growth of tumors. The process of new blood vessel formation is under complex control from a variety of pro- and anti-angiogenesis factors. By identifying and understanding these factors, new therapies have been developed to inhibit tumor growth and survival by blocking tumor-related angiogenesis. Recent success with the monoclonal antibody against vascular endothelial growth factor (VEGF; bevacizumab) in a large, randomized, phase III study has provided a critical proof of principle for this therapeutic area. This review will outline the biology of angiogenesis in colorectal cancer and discuss the current status of angiogenesis inhibition in its treatment.