Ranibizumab (Lucentis) is a Fab-Antibody with high affinity for VEGF, and is being designed to bind to all VEGF isoforms. This quality makes it a powerful drug for VEGF inhibition. Diseases of retinal and choroidal blood vessels are the most prevalent causes of moderate and severe vision loss in developed countries. Vascular endothelial growth factor plays a critical role in the pathogenesis of many of these diseases. Results of the pilot studies showed that intraocular injections of ranibizumab (Lucentis) decrease the mean retinal thickness and improve the BCVA in all the subjects. Proliferative diabetic retinopathy, currently treated with destructive laser photocoagulation, represents another potential target for anti-VEGF therapy. The early experience in animal models with proliferative retinopathy and neovascular glaucoma shows that posterior and anterior neovascularizations are very sensitive to anti-VEGF therapy. The outcome of two phase III clinical trials will increase our knowledge of the role of Lucentis in the treatment of DME.