Background:Paravalvular leak(PVL) is a troublesome issue after valve replacement. As pressure gradient across the valve is more markedly increased in PVL occurring at mitral position which happens at systolic phase,hemodynamic results could be different between PVL after MVR and AVR.Therefore, we hypothesized that clinical outcome of PVL after AVR would be better than that after MVR.Methods:The outcomes of PVL between 1997 and 2008 were analyzed. The patients who required immediate surgical repair due to severe symptoms, or requiring repeated blood transfusion were excluded. Patients with Behcet���s disease, infective endocarditis and PVL involving both valves were also excluded. 20 patients with AVR and 27 patients with MVR, who were not indicated for surgery were included for analysis.Results:During a mean follow-up of 112짹88 months, there were 4 repeat surgeries, 1 cardiac death, and 2 non-cardiac deaths in the AVR group, whereas 19 repeat surgeries, 1 cardiac death, and 1 admission for heart failure in MVR group. The estimated 8-year event-free survival rate was significantly higher in the AVR group than that of MVR group (55짹15% vs. 17짹9%, p=0.003).Conclusion:PVL after AVR demonstrated more favorable long-term clinical outcomes compared with that after MVR. Therefore, patients who develope PVL after AVR, repeat surgery can be deferred. However, following MVR, a more aggressive surgical treatment of PVL should be considered even for the patients who are less symptomatic and for those not requiring repeated transfusion.