We present a case of a giant fenestration and a fibrous strand rupture of the aortic valve without massive regurgitation. A 56-year-old woman, was referred for coronary revascularization, had II–III degree aortic regurgitation without symptoms of heart failure. On the intraoperative direct view, the non coronary cusp (NCC) had the giant fenestration and the left coronary cusp (LCC) had the fibrous strand rupture. There was no severe inflammation, thrombi, or vegetation. Finally, she had coronary artery bypass surgery and aortic valve replacement. Although fenestration of the aortic valve is not rare, it is hard to determine its configuration preoperatively. When the echocardiographic findings indicate an eccentric regurgitation flow despite the absence of prolapse, we should perform examinations with the possibility of coexisting aortic valve fenestration in mind. Massive regurgitation does not necessarily correspond to a giant fenestration and a fibrous strand rupture. We report a rare case of the unusually large fenestration and the rupture of the fenestrated fibrous strand of the aortic valve without massive regurgitation.