The aim of this study was to determine the surgical results of repair of coarcta tion of the aorta in children under 1 year of age and to assess the risk of recoarctation. Between 1984 and 2004, 206 children under 1 were operated for coarctation of the aorta. Three groups of patients were identified: Group I (isolated coarctation, N=99), Group II (associated ventricular septal defect, N=63), and Group III (complex congenital heart disease, N=44). The transverse aorta was hypoplastic in 51% of cases. Uni- and multivariate analysis of the risk factors for mortality and recoarctation was performed. An extended resection anastomosis was performed in 206 patients. Reconstruction of the transverse aorta was performed in 32 cases. The hospital mortality was 3.9% (N=8). The presence of a complex intracardiac anomaly was a risk factor for mortality on multivariate analysis (p=0.023). In univariate analysis, a two-step management of patients in Group III was a significant risk factor for mortality (p=0.036). Thirty patients (14.6%) had recoarctation (gradient > 20 mmHg, follow-up 40 +/- 44 months). On multivariate analysis the severity of the immediate postoperative gradient was the only risk factor for recoarctation. The authors conclude that surgery for coarctation of the aorta is associated with excellent results in children under 1 year of age. The prognosis is related to the presence of associated severe cardiac malformations. Survival seems to be better if treatment is carried out in a single stage in this group. The risk of recoarctation is related to the immediate postoperative transisthmic gradient which justifies extensive repair of hypoplastic aortic arches.