Between September 1986 and January 1994, 129 St. Jude Medical prostheses were implanted in 113 patients who were 18-year-old or younger at the Cardiovascular Surgery Clinic of Turkiye Yuksek Ihtisas Hospital. Thirty-seven patients underwent aortic, 60 patients mitral and the remaining 16 patients double valve replacement. Overall hospital mortality was 7.9% (9/113). All patients received 2.5 mg/day warfarin from the first postoperative day, in addition 225 mg/day dipyridamole and 100 mg/day aspirin was given following the removal of mediastinal tubes. This regimen was continued indefinitely thereafter. Follow up period ranged between 2-94 months. Total follow up experience was 276.4 patient-years. There were five late deaths; the cause of death was prosthetic valve thrombosis in two patients, intracerebral hemorrhage in one, cardiomyopathy in one, and sudden death in one. Other late complications included one endocarditis, a further anticoagulant related bleeding and one paravalvular leak. There was no case of cerebral or peripheral embolism reported. Seven-year actuarial survival was 92.4 +/- 6.8% for the entire group, 84.6 +/- 13.8% after mitral and 100% after aortic or double valve replacement. In conclusion, low dose oral anticoagulation after heart valve replacement with St. Jude Medical prosthesis in this age group showed satisfactory clinical results.