Despite improving surgical techniques, treatment of heart valve disease in children remains controversial. Growth of the child and adequate anticoagulation level are the main concerns when valve replacement is performed in the pediatric age. We reviewed the case histories of 29 children who underwent valve replacement with mechanical prosthesis from 1979 to 1994 in order to evaluate the performance of mechanical valves in this age group. Age ranged from two years to 12 years (mean 8.97 +/- 3.7 years). A total of 31 valves were implanted; 17 children had atrioventricular (Av) valve replacement (15 mitral, one common Av (heterotaxia), one tricuspid (systemic ventricle)), 11 children had aortic valve replacement (one redo), and one child had double mitral and aortic valves implanted. The etiology of valvular disease was congenital in 34.5%, degenerative in 17.2%, rheumatic in 24%, infective in 13.8%, and prosthetic dysfunction in 10.3%. Of the 29 patients, eight had undergone previous procedures and eight required simultaneous repair of associated lesions. There were three hospital deaths (10.3%). The mean follow up was 5.79 +/- 5.36 years. There were four late deaths (2.66%/patient-year) at a mean of 37 months from surgery. All operative survivors received oral anticoagulation with sodium warfarin. No thromboembolic event or bleeding occurred, no endocarditis developed in any patient; one reoperation was performed for patient/prosthesis mismatch. Mechanical valves offer excellent hemodynamic performances and a low rate of thromboembolism and/or bleeding in our experience, and are our first choice for heart valve replacement in children when reparative surgery is not feasible.