Background: Aortic cusp extension is a technique for aortic valve (AV) repairs in pediatric patients. The choice of the material used in this procedure may influence the time before reoperation is required. We aimed to assess post-operative and long-term outcomes of patients receiving either pericardial or synthetic repairs.Methods: We conducted a single center, retrospective study of pediatric patients undergoing aortic cusp extension valvuloplasty (N=38) with either autologous pericardium (n=30) or CorMatrix (n=8) between April 2009 and July 2016. Short and long-term postoperative outcomes were compared between the two groups. Freedom from reoperation was compared using Kaplan Meier analysis. Degree of aortic stenosis (AS) and aortic regurgitation (AR) were recorded at baseline, post-operatively, and at outpatient follow-up.Results: At five years after repair, freedom from reoperation was significantly lower in the CorMatrix group (12.5%) compared to the pericardium group (62.5%) (P = 0.01). For the entire cohort, there was a statistically significant decrease in the peak trans-valvar gradient between pre- and post-operative assessments with no significant change at outpatient follow-up. In the pericardium group, 28 (93%) had moderate to severe AR at baseline which improved to 11 (37%) post-operatively and increased to 21 (70%) at time of follow-up. In the biomaterial group, 8 (100%) had moderate to severe AR which improved to 3 (38%) post-operatively and increased to 7 (88%) at time of follow-up.Conclusion: In terms of durability, the traditional autologous pericardium may outperform the new CorMatrix for AV repairs using the cusp extension method.