The aim of this study was to determine whether the use of an ileal Roux limb, rather than a jejunal Roux limb, would prevent the Roux stasis syndrome that can occur after Roux gastrectomy. An ileal Roux limb was constructed in eight dogs and anastomosed to the gastric remnant after distal hemigastrectomy. Flow of chyme through the jejunum was preserved via an ileojejunostomy and a jejunoileostomy. Six dogs with distal gastrectomy and a conventional Roux gastrojejunostomy served as a control group. Chronic enteric recording electrodes and intraluminal, open-tipped pressure catheters were implanted in all dogs. After recovery, the electrical activity and motility of the Roux limbs and the rates of gastric emptying of liquids and solids were measured. Dogs with a Roux gastroileostomy had a slower frequency of pacesetter potentials in the Roux limb, a greater Roux motility index, and a faster rate of gastric emptying of liquids and solids than did dogs with a Roux gastrojejunostomy. Stomal ulcers, however, developed in seven of the eight ileal Roux limbs but in none of the jejunal Roux limbs. It was concluded that Roux gastroileostomy does ameliorate the Roux stasis syndrome, but there is a greater risk of stomal ulceration in the limb.