Report of one case of a Laubry and Pezzi syndrome. In spite of the already severe aortic incompetence at the age of 4 years, operation was postponed. Three years later, at the first signs of bad tolerance of the aortic incompetence the operation was undertaken including: -- closure of the ventricular septal defect by a patch, and correction of aortic incompetence by a metallic-ball Starr's prosthesis n 9. After an observation period of 18 months, the result of operation is satisfactory, in spite of signs of haemolysis. Comparison with the data from the literature led to the following conclusions: 1) in a patient with ventricular septal defect the demonstration of a diastolic murmur indicates closure of the septal defect. 2) When the aortic incompetence is a severe one, it should be corrected urgently, whatever the age of the child, if badly tolerated. In the very young child, if it is well tolerated, the operation might be postponed in view of the difficulties of plastic operations and the hazards of prostheses in such patients. 3) A moderate aortic incompetence constitutes the most difficult indication; a conservative operation seems to be preferable to a valve replacement by a prosthesis, a homograft or a heterograft. The results obtained by some techniques of valvular plasty after observation periods amounting to 12 years are considerable.