We report a rare case of a 58-year-old male with accidental occlusion of left main trunk (LMT) artery by injured aortic valve during percutaneous coronary intervention (PCI). Although we successfully bailed out this complication by urgent LMT stenting, aortic regurgitation developed immediately after PCI. Echocardiography detected a filamentous structure attached to the aortic valve. An elective aortic valve replacement surgery revealed that his right coronary cusp was torn into two filamentous strips. One strip accidentally plunged into LMT and was fixed by the intracoronary stent. Another strip floated in the aortic root and appeared as though vegetation attached to the aortic valve in case of acute infective endocarditis. Guiding catheters probably injured the aortic valve during PCI. This report reminded us of the importance of meticulous manipulation of a guiding catheter.