Aortic root cineangiography has been carried out in 21 consecutive survivors of replacement of the aortic valve with a Starr-Edwards ball-valve prosthesis. In nine of 21 patients, a significant leak around the rim of the prosthesis was demonstrated. In four reoperated patients, this leak was confirmed to be secondary to disruption of the suture material, usually in patients with heavily calcified annuli. Cineangiographic studies are necessary for complete postoperative evaluation of prosthetic values.