Congenital pyloric atresia is a relatively unusual condition. From three cases the authors point out the diagnosis basis. The main clinical findings are hydramnios, early non bilious vomiting and epigastric distension. Diagnosis is based upon abdominal plain films. They demonstrate an air dilated stomach, and no air distal to the pylorus. When films can be taken in the upright position, they demonstrate a single intragastric air-fluid level. Radiologic findings are essential, because surgical inspection alone fails to demonstrate membranous atresia and cordonal atresia which are more frequent than total atresia. In the two former conditions, radiologic findings lead the surgeon to look for the obstruction by the mean of a catheter introduced by a juxta-pyloric antrotomy.