We conducted retinal neovascularization under subfoveal fibrotic nodule for Coats disease by using optic coherence tomography-angiography before and after ranibizumab treatment. Our patient was an 8-year-old boy who was referred with suspicious left retinal mass. His visual acuity was 20/400 in the left eye and 20/20 in the right eye at the time of admission. Posterior segment evaluation of the left eye revealed telengiectatic vessels at the inferotemporal region of the peripheral retina with hard exudates around the optic disc and macula typical for Coats disease. His optic coherence tomography revealed a subfoveal fibrotic nodule after ranibizumab injections and laser photocoagulation treatment. The optic coherence tomography-angiography results revealed neovascularization under the subfoveal nodule at the superficial vascular complex layer. After 3 intravitreal ranibizumab injections, his neovascularization regressed on optic coherence tomography-angiography and his visual acuity improved. To the best of our knowledge, this is the first report demonstrating neovascularization under the subfoveal fibrotic nodule in Coats disease on the basis of comparative with the help of optic coherence tomography-angiography before and after the treatment.