In 12 children aged from 1 day to 15 years with various kinds of congenital gastrointestinal anomaly (atresia/stenosis in the duodenum, jejunum, or ileum; duplication cyst in the duodenum/Bauhin's valve; ectopic pancreas antropyloric) the almost invariably present disturbance of passage was sonographically documented and located and, in the cases with concomitant processes of the bowel wall, the causative lesion demonstrated. In 3 neonates, the diagnosis including complications (meconium peritonitis with calcifications secondary to small bowel perforation) had already been accurately made prenatally. Despite the always unequivocal ultrasound findings, additional x-ray examinations (only plain in 5, only with contrast medium in 1, plain and with contrast medium in 6 cases) were performed in all patients to confirm the diagnosis and reassure the operator. Comparison of the sonographic with the radiological and, later, with the surgical results showed that, in all cases, ultrasound had already provided the information essential to the surgical intervention. The results indicate that, in future, a substantial reduction of additive x-ray examinations is possible in such diseases and that their early intrauterine sonographic documentation should be attempted much more frequently.