Angiogenesis, the process of generating new capillary blood vessels, is a fundamental requirement for normal physiological processes including embryogenesis, reproductive function and wound healing. Angiogenesis is also implicated in various pathological conditions including age-related retinal macular degeneration, diabetic retinopathy, rheumatoid arthritis, psoriasis and cancer growth and metastasis. Vascular endothelial growth factor (VEGF) is one of the best characterized of the pro-angiogenic growth factors, and multiple strategies have been developed to inhibit this pathway. Bevacizumab, a monoclonal antibody developed against VEGF, has shown initial preclinical and clinical activity. This review discusses the critical role of VEGF and summarizes the available data on the use of bevacizumab in colorectal cancer.