Objective: To evaluate the evolution of under 15-year-old patients suffering from mitral valve reflux submitted to mitral valve repair surgery. Method: A total of 117 under 15-year-old patients, submitted to mitral valvuloplasty from May 1980 to November 2001 were evaluated. Their ages ranged from 1 to 15 years old, with a mean age of 10 years. Seventy-four patients (63.2%) were female. The most common etiology was rheumatic disease (81.2%). Eighty-seven patients (74.4%) presented with mitral valve reflux and 30 (25.6%) also suffered from stenosis. Other diseases were associated in 28 patients (23.9%) with aortic valve disease being the most common (13.7%). Several techniques were employed for valve repair such as the shortening or lengthening of the chordae tendineae and papillectomy. Results: Late evolution demonstrated that 96.6% of the patients survived and 88.9% retained their native valves. Fifteen patients (12.8%) underwent reoperations. The mitral valve was remodeled in all patients, with Gregori-Braile rings used in 69 (58.9%) and Carpentier rings in 35 (29.9%). The most commonly used techniques were shortening of the chordae tendineae in 66 patients (56.4%), and commissurotomy and/or papillectomy in 30 patients (25.6%). There was 1 hospital death (0.9%) and 3 late deaths (2.6%). Conclusions: Reconstruction surgery to treat reflux of the mitral valve is possible, presenting results that support its use in under 15-year-old patients. Descriptors: Mitral valve, children. Mitral reflux, repair techniques. Resumo Objetivo: Avaliar a evolução dos pacientes portadores de regurgitação valvar mitral menores de 15 anos submetidos à operação reconstrutora da valva mitral. Método: Cento e dezessete pacientes com idade inferior a 15 anos, submetidos à plastia valvar mitral, no período de maio de 1980 a novembro de 2001. A idade variou de 1 a 15 anos, com média de 10 anos. Setenta e quatro pacientes (63,2%) eram do sexo feminino. A etiologia mais freqüente foi a doença reumática (81,2%). Oitenta e sete pacientes (63,2%) apresentavam regurgitação mitral e 30 (25,6%) Resultados da operação reconstrutora da valva mitral em pacientes com idade inferior a 15 anos Outcomes of mitral valve repair surgery in under 15-year-old patients 116 CORDEIRO, CO ET AL-Outcomes of mitral valve repair surgery in under 15-year-old patients