Sixty Carpentier-Edwards porcine valve bioprostheses stabilized with glutaraldehyde were implanted in 55 patients with acquired and congenital heart disease. The follow-up period ranged between 1 and 12 months. There were 3 hospital deaths (5%) and 2 late deaths (4%) in 24 mitral, 24 aortic, 5 mitral-aortic, 1 tricuspid and 1 pulmonary valve replacements. All patients were anticoagulated from the second postoperative day onwards for a period of 3 months after which those with sinus rhythm had their anticoagulants withdrawn. Paravalvular leakage led to re-operation in 3 cases (4%). No valve failure due to cusp rupture was encountered and no thromboembolic complications have occurred. Thirty-three patients were studied postoperatively by non-invasive methods and the results are presented.