OBJECTIVE To explore the gene expression patterns of choroidal neovascularization with gene chip technology. METHODS Total RNA was isolated from normal choroid and choroid tissues with neovascularization induced by krypton laser photocoagulation in Brown Norway rat. The mRNA was purified and was reversely transcribed to cDNA to prepare for hybridization probes. In choroidal neovascularization, the differentially expressed genes were assayed with gene chips which contained 5705 rat genes. RESULTS There were 46 genes expressed differentially in choroidal neovascularization. Of these, the expression of 3 genes was upregulated and 43 genes downregulated. These genes were involved in the function of transport, signal, metabolism, development and differentiation of cell adhesion. CONCLUSIONS Numerous genes are involved in the development of choroidal neovascularization induced by krypton laser photocoagulation.