BACKGROUND: Deciding which prosthetic aortic valve to choose is difficult in adolescents who have not yet met their full growth potential. The aim of this study was to assess long-term outcomes following mechanical aortic valve replacement with aortic root enlargement in adolescents. METHODS: Between September 1997 and December 2006, 58 consecutive adolescents (49 male, 9 female, median age 15.5, range 13 to 17 years) underwent mechanical aortic valve replacement with aortic root enlargement. All patients received long-term anticoagulation treatment with warfarin, aiming to maintain an international normalized ratio between 2.0 and 2.5. Follow-up of all patients was closed in December 2015. RESULTS: The mean size of implanted valves was 20.1 +/- 1.3 mm. There were two operative deaths (3.4%) and one late death (1.7%). Mean follow-up was 11.6 +/- 3.3 years (range, 8.5 to 15.8 years). Actuarial survival at 15 years was 94.7 +/- 3.2%. No patient required a redo procedure. At the latest clinical evaluation, 47 patients (81.0%) were in New York Heart Association functional class I and 8 (13.8%) were in functional class II. Actuarial freedom from valve-related complication was 88.1 +/- 2.8% at four years. The mean gradient across the aortic mechanical valve on echocardiography was 13.2 +/- 6.3 mmHg (range 6 to 38 mmHg). CONCLUSIONS: Mechanical aortic valve replacement with aortic root enlargement remains an excellent treatment option in adolescents with full growth potential. The mortality is very low and all surviving patients resumed normal lifestyles. It represents a good alternative to allografts and bioprostheses in adolescent patients with aortic valve disease.