In children with growth retardation and the typical face, particularly with valvar pulmonary stenosis, the Noonan syndrome is the be suspected. In early infancy, these patients show very severe developmental retardation and muscular hypotony. Mental retardation is frequent but not compulsory. The most important diagnostic tool is the chromosomal analysis. In our patient, the syndrome was diagnosed becaused of the typical appearance and the angiocardiographic findings in connection with a normal chromosomal sequence.