In a retrospective trial we investigated the significance of ultrasound in the diagnosis of intestinal obstruction in 459 patients. The overall sensitivity was 93.7%. In paralysis the correct diagnosis was obtained in 98% of all. Mechanical obstruction was identified in 91%. In cases of incomplete mechanical obstruction sensitivity was 89%. The corresponding value for complete obstruction was 95%. In all patients with negative findings on abdominal x-ray (10%) the correct diagnosis was established by ultrasound. Only in 71 % of cases ultra-sound was successful differentiating small bowel from large bowel obstruction. The underlying cause of ileus was yielded by ultrasound in 45 % of the cases. On the basis of our experience ultrasound is proven to be of significant importance in the diagnosis and differentiation of ileus.