Genistein is a dietary-derived flavonoid abundantly present in soybeans and known to possess various biological effects including anti-inflammation and anti-angiogenic activity. To investigate the effects of genistein on intraocular neovascularization, we used an animal model of laser-induced choroidal neovascularization (CNV). Male C57BL/6J mice were treated in accordance with the ARVO Statement for the Use of Animals in Ophthalmic and Vision Research. CNV was induced by laser photocoagulation. The animals were fed a mixture diet containing 0.5% genistein or a control diet ad libitum for 7 days before laser photocoagulation and the treatment was continued until the end of the study. Seven days after laser injury, the size of CNV lesions was quantified. Retinal pigment epithelium (RPE)-choroid complex was also harvested 1 or 3 days after laser injury and the level of monocyte chemoattractant protein (MCP)-1, intercellular adhesion molecule (ICAM)-1, and matrix metalloproteinase (MMP)-9 were measured by enzyme-linked immunosorbent assay. Expression levels of Ets-1 and F4/80 were examined by real-time PCR. A significant decrease in CNV size was observed in animals treated with genistein (15441.9±1511.8 μm(2)) compared to control mice (21074.0±1940.7μm(2), P<.05). Genistein significantly reduced the protein level of MCP-1, ICAM-1, and MMP-9 in the RPE-choroid complex (P<.05). In addition, genistein suppressed the expression levels of Ets-1 and F4/80 (P<.05). The current data indicate the anti-angiogenic property of genistein during CNV formation.