Development of aortic valvular deformities was studied retrospectively in 395 inpatients with subarterial infundibular ventricular septal defect (siVSD). Aortic valvular deformities included prolapse into siVSD without aortic regurgitation (77 patients), prolapse and aortic regurgitation (95 patients), and aneurysm of the sinus of Valsalva (36 patients). No aortic valvular deformity was found in 187 patients, and 111 of these 187 patients had associated pulmonary hypertension. Prolapse and regurgitation of the aortic valve developed most frequently at the age 5 to 8 years. Aneurysm of the sinus of Valsalva was not found before the age of 10 years but began to develop during the teens and was diagnosed most frequently in the twenties. Patients with pulmonary hypertension did not develop aortic valvular deformities except in one instance. All inpatients with siVSD and without pulmonary hypertension over the age of 30 years had developed some aortic valvular deformities.