THIS report summarizes our experience with 350 cases of duodenal ulcer subjected to bilateral vagotomy and followed for periods varying from six to 45 months. The project has been a joint responsibility of the Surgical Service and the Gastro-Enterology Section of the Medical Service, aided by the close collaboration of the departments of radiology, pathology and psychiatry. SELECTION OF PATIENTS In general, the indications for vagotomy in our patients have been similar to those usually considered for other types of surgery in the treatment of duodenal ulcer and its complications. Medical intractability was determined not only by a past history of inadequate medical response but also by the observation of the response to therapy under a rigid hospital program, usually for four weeks. It has been our experience that the chances of success with medical treatment are decidedly poor if the patient fails to show improvement with hospital therapy within