A 35-year-old woman who had left coronary ostial stenosis and aortic valve regurgitation due to Takayasu's aortitis underwent transaortic patch enlargement of the stenosed left coronary ostium in combination with aortic valve replacement. This technique may be suitable and recommendable as an alternative to aortocoronary bypass grafting or endarterectomy for coronary ostial stenosis in Takayasu's aortitis.