The patterns of aortic and tricuspid valve motion in 50 patients with mitral valve prolapse were analyzed by wide-angle, phased-array, two-dimensional echocardiography. Twelve patients (24%) had redundant aortic leaflets bulging into the left ventricular outflow tract during diastole. Eight of 12 patients had aortic regurgitation and seven of 12 had M-mode echocardiographic evidence of aortic valve prolapse. One patient underwent mitral and aortic valve replacement, and the excised valves revealed marked myxomatous degeneration. Eight of 15 patients undergoing contrast echocardiography had tricuspid regurgitation (systolic reflux of contrast material into the inferior vena cava persisting for more than 10 beats), and prolapse in the septal leaflet of the anterior leaflet or both. A similar tricuspid valve pattern was noted in three of seven patients without tricuspid regurgitation. Tricuspid valve prolapse was identified in 20 patients (40%). Nine patients (18%) had combined prolapse of the mitral, aortic and tricuspid valves. In five patients with middiastolic high-pitched murmurs recorded along the left sternal border, tricuspid valve prolapse was demonstrated. In one of these patients, the presence of pulmonary regurgitation was confirmed by intracardiac phonocardiography. We conclude that two-dimensional echocardiography is useful for evaluating patients with combined valvular prolapse syndrome.