[Abstract] The surgical outcomes of pediatric valve replacements are poor, and these patients require long-term anticoagulation therapy, management and evaluation strictly for serious complications which include late prosthetic valve stenosis and infections. Each facility only deals with a small number of cases, and only a limited number of facilities manage patients who undergo repeated operations as they develop. Because no clear indicators for the timing of repeat valve replacements due to longterm growth have been reported, we examined a new additional indicators. We examined the postoperative courses of 18 patients who underwent left atrioventricular valve replacement during infancy at our hospital from May 1979 to December 2018. Rowlatt\u27s normal mitral annulus diameter was used as an indicator of valve size. There were 2 deaths in the initial operation and 5 late deaths. These were 5 patients underwent repeated valve replacements. Valve thrombi occurred in 2 patients. The avoidance rate of valve-related complications was 71% and 62% at 5 and 10 years, respectively. The avoidance rate of repeat valve replacement due to growth was 95% and 87% at 5 and 10 years, respectively. When valves were replaced,all patients were implanted with a prosthetic valve 2 sizes larger than in the initial operation. In the patients we examined, repeat operations due to growth were performed when the area of the prosthetic valve was less than 70% of Rowlatt\u27s criteria. Although repeat valve replacements are inevitable with growth, it may be possible to predict the timing of repeat interventions