, 20 children 2 to 18 years of age underwent valve replacement with the St, Jude Medical prosthesis. Nine children underwent aortic valve replacement, eight underwent mitral valve replacement, and the three children with corrected transposition underwent left-sided tricuspid valve replacement. Of the 20 patients, 17 underwent 23 previous procedures. AU but five patients received adequate adult-sized prostheses. There was one hospital death (5 %). AU hospital survivors received maintenance doses of sodium warfarin. FoUow-up was 100% complete with a total of 106 patient-years. There were no late deaths and no thromboembolic or anticoagulant-related bleeding. None of the patients had prosthetic valve endocarditis or a periprosthetic leak. Reoperation was not required in any patient. The great majority of the children (16 of 19) were in New York Heart Association functional class I, two were in class Il, and one with complex congenital heart disease was in class In at the time this article was written. This study illustrates the excellent results of cardiac valve replacement with the St. Jude Medical prosthesis in children and confirms the safety of sodium warfarin in this age group.