The experience of surgical treatment of 55 congenital mitral incompetence patients aged 3 to 34 years is analysed. Patients with the anomalies of the conotruncus, mitral stenosis, and open atrioventricular conduit were not included into the analysis. The preoperative clinical status of all the patients was evaluated as functional class III-IV. Twenty-one patients had attendant septal defects. Lung hypertension of group II was seen in 14 patients and of hemodynamic group IIIA in five patients. Pronounced disorders of intracardiac hemodynamics and circulatory impairments were indications to an operation. Failure of the mitral valve to close was secondary to several developmental defects. Deformities of the septa and of the chordal and papillary apparatus varied greatly. The mitral incompetence degree was aggravated in most patients by dilatation of the fibrous ring. The diversity of the morphological causes underlying mitral incompetence dictated a strictly individualized approach to the choice of the type and volume of a surgical intervention. Ten of the 55 patients underwent mitral valve replacement; various types of valvuloplasty were done to 45 patients. General hospital mortality rate was 10 percent; good and satisfactory outcomes were seen after reconstructive operations. Analysis of the outcomes of surgery for congenital mitral incompetence has shown that reconstructive operations on the valve are effective enough and may be recommended as a method of choice. Annuloplasty is required in most reconstructive procedures; in young children preference should be given to suture annuloplasty.