Aortic regurgitation is occasionally caused by fibrous strands and more rarely by downward displacement of the aortic annulus. The present report describes an 18-year-old man with aortic regurgitation resulting from an anterior-posterior type of bicuspid aortic valve with fibrous strands and downward displacement of the anterior aortic annulus. A pair of fibrous strands at the anterior cusp of the bicuspid valve lifted the free margin of the cusp, and the anterior cusp originated from the intraventricular septum. We considered that the aortic regurgitation was due to poor coaptation of the cusps because of these two conditions. After resection of the cusps and the strands, the aortic valve was replaced at the intra-annular position.