Purpose: The purpose of this study was to report a 30-year-old woman with Eales disease, showing bilateral proliferative tissue. The retinal vessels were evaluated using widefield optical coherence tomography angiography (widefield OCTA), which has a wider angle of view compared with conventional instruments. Methods: This is a case report. Results: Widefield OCTA showed an extensive nonperfusion area and A-V shunt in both eyes and a vascular structure in the left eye that appeared to be retinal neovascularization. Ultra-widefield fluorescein angiography revealed no filling delay in the early phase, a vast nonperfusion area from the midperiphery to the ora serrata in bilateral eyes, and retinal neovascularization in the left eye. Based on the results of ultra-widefield angiography, OCTA examination, and systemic examination, a diagnosis of Eales disease was finally made after all the differential diseases had been excluded. Conclusion: In a patient with Eales disease, the peripheral nonperfusion area and retinal neovascularization that were consistent with the ultra-widefield angiography findings were noninvasively confirmed by widefield OCTA. Widefield OCTA is useful in the detection of peripheral changes of the fundus.