A new instrument for accomplishing inverted stapled anastomoses in the gastrointestinal tract is described. Side-to-side, end-to-side and end-to-end anastomoses can be performed. Techniques developed for utilization of the instrument in virtually all gastrointestinal anastomoses are described. In most instances a proximal or distal enterotomy is required. Experience with 57 anastomoses in 42 patients is reported. One leak occurred; no other complications not recognized intraoperatively were observed. Anastomoses completed included gastroduodenostomy, gastrojejunostomy, cholecystojejunostomy, colocolostomy and ileocolostomy. Hazards and complications associated with the use of the instrument are described. It should be used only after the surgeon has acquired the skills to operate the instrument properly. The instrument saves time, creates better anastomoses than can be obtained by hand sewing and is extremely versatile. It may permit safer anastomoses in adverse conditions, such as in obstruction and peritonitis. The instrument opens new horizons in gastrointestinal surgery.