Sixty-six children aged between 8 months and 15 years (average age 5.5 +/- 3.8 years) underwent mitral reconstructive operations for congenital mitral regurgitation between June 1969 and February 1987. The pathologic findings of the mitral valves were annular dilatation in 37 patients, cleft of the leaflet in eight, hypoplasia of the leaflet in 44, perforation of the leaflet in one, chordal elongation in 22, chordal absence in 16, and chordal shortening in seven. The methods of repair consisted of asymmetric annuloplasty (Kay-Reed method) in 61 patients, De Vega-type annuloplasty in one, plication of redundant leaflet in 15, and closure of cleft or perforation in nine. The single operative death (1.5%) was due to heart block. Follow-up data were available over 373.8 patient-years (average 5.7 years). The four late deaths (6.0%) were due to heart failure in two patients, pneumonia in one, and hepatitis in one. The actuarial survival rate was 93.1% +/- 3.1% at 7 years and 88.4% +/- 5.1% after 17 years. Valvuloplasty failed in 19 of the long-term survivors. One of these patients underwent mitral valve replacement 11 years after initial operation. The rate of freedom from reoperation was 86% +/- 10% after 17 years. The rate of freedom from valvuloplasty failure was 80% +/- 6.7% after 5 years, 67% +/- 7.2% after 10 years, and 44% +/- 11.9% after 15 years.