Objective · To investigate the role of interleukin-10 (IL-10) in regulating ocular neovascularization (NV). Methods · Expression of IL-10 was investigated in mice with oxygen-induced retinopathy (OIR) and transgenic mice with VEGF expression in photoreceptors by immunofluorescence, RT-PCR, and Western blotting. Mice deficient in IL-10 were used to test the effect of IL-10 in retinal, sub-retinal, and choroidal NV. Results · In OIR mice and transgenic mice with VEGF expression in photoreceptors, the staining intensity and mRNA expression of IL-10 were increased. Mice deficient in IL-10 showed a significant reduction in ischemia-induced retinal NV, and choroidal NV at rupture sites in Bruch’s membrane. Mice lacking IL-10 showed reduced levels of hypoxia-inducible factor-1α (HIF-1α) and suppression of ischemia-induced expression of VEGF and VEGF receptor 1. Macrophage was regulated and reduced in ischemic retina of mice with IL-10 deficiency. Conclusion · IL-10 stimulates ocular NV through modulation of HIF-1α and its target genes VEGF and VEGF receptor 1. IL-10 promotes ocular NV via macrophage response to retina ischemia.