From 1972 to 1985, the first 100 children suffering from some form of atrio-ventricular septal defect underwent surgical correction. In all cases, corrective surgery was carried out primarily except in 3 children who presented with a total defect and first underwent palliative surgery. In 48 children, a complete form was present, in 5 an intermediate form, and in 47 a partial form. There were 43 males and 57 females. Thirty-eight percent of patients suffered from Down's syndrome. The mean age at operation was 42 (range 2-143) months. A prosthesis was implanted in the left atrio-ventricular valve at primary correction in 9 patients. Up to 1980, the overall mortality was 20% and from 1981 to 1985 it was 3.3%. There was late mortality in 3 children (2 with a complete form and 1 partial). In 32 cases, postoperative cardiac catheterization was performed. Nine patients were reoperated upon (9%), 2 due to a residual shunt, 4 due to serious mitral incompetence (in all cases a prosthesis was used), and 3 due to valvular thrombosis. In this series, only 2 patients remained in complete atrio-ventricular block (1 affected by the complete form and the other partial). Long term survival is related to the severity of left valvular insufficiency. In this series with a mean follow-up of 3.83 +/- 2.78 years, we had an a cumulative survival of 86.7% +/- 3.43%. At the last control, most of the survivors had a good quality of life: 91% were in class I and 9% in class II according to the NYHA scale.