Eighteen cases of surgically confirmed VSD with AI were evaluated retrospectively during the period of 3 years from Jan. 1985 to Dec. 1987 at hanyang University. All cases were examined by biplane cine-Angiography. the main points of angiographic evaluation were degree of aortic regurgitation and which aortic cusp being prolapsed. The results were as follows:1. The male to female ratio was 12 to 6 . The age distribution was rather broad from 4 months to 25 years. Most of them is inthe age group between 6 to 15 years old.2. The severity of the aortic regurgitation was increased according to the age of the patient. 3. Surgically congirmed subarterial type VSD were 12 cases twice as frequent as perimembr-anous VSD. 4. The angiographic and surgical findings were matched in 15 cases. The 3 mis-matched cases were confirmed surgically as subarterial type of VSD but diagn-osed as perimembranous type angiographically. 5. The site of the prolapse of the aortic cusp was helpful for classification of the type of VSD: In subarterial type of VSD only the right coronary cusp was prolapsed but in perimembra-nous type there were prolases of the right coronary cusp or non-coronary cusp or both. 6. In subarterial type of VSD the left upper portion of the right coronary cusp was prolapsed. and right lower portion of cusp in perimembranous type. 7. Valvuloplasty or valve replacement was needed in the patient with severe aortic regurgita-tion.