The arterial blood supply of the anastomosis in 6 stomach resected dogs (Billroth II) is examined by common angiographic technique in vivo, microangiography, and microscopy. In all animals there are at the site of the gastrojejunostomy bizarre tortuous vessels which cross the anastomosis. These arteries have a diameter between 50 to 2000 mu. They are newly formed vessels which cannot be demonstrated by common coeliaco- and mesentericography in animal experiments or in patients.