Although platinum-based chemotherapy remains a mainstay of non-small-cell lung cancer treatment, its efficacy has probably reached a plateau. Increased understanding of cancer biology has allowed the identification of a number of possible molecular targets, including the EGF receptor and the angiogenesis pathway. ECOG-E4599 has randomised chemonaive patients to receive paclitaxel--carboplatin with and without bevacizumab, a humanised monoclonal antibody targeting the VEGF. The study is the first to show a survival advantage of adding a biological agent to chemotherapy in this setting: in particular, for the first time the survival of lung cancer patients has been extended beyond 1 year. The aim of this review is to describe the biological and clinical properties of bevacizumab and to discuss the evidence that has supported its approval for the first-line treatment of advanced non-squamous non-small-cell lung cancer.