Between September 1st 1974 and June 1st 1976, 12 infants under the age of 6 months have been operated on by a dacron patch aortoplasty for coarctation of the aorta. The associated lesions were a patent ductus arteriosus in each case, a VSD in 8 cases, and a trans-position of the great arteries in 5 cases. A pulmonary artery banding was performed with the aortoplasty in 8 cases, and a Blalock-Hanlon operation in one instance. There were two operative deaths (17 p. 100), amongst them one in a 1400 g premature infant, and a late death (3rd month). Two infants have a clinical aspect of recoarctation. In four infants, the post-operative hemodynamic and angiographic study carried out before the treatment of associated intra-cardiac lesions, shows a good result of the coarctation repair. This particular technique, although not performed as a routine in the infant with coarctation of the aorta, seems to be of interest in the most severe forms of the disease, with diffuse isthmus narrowing and intra-cardiac defects.