Primary adenocarcinoma of the duodenum is rare. An extensive experience with fiberoptic esophagogastro-duodenoscopy in our institution has indicated that duodenal neoplasms may be more frequent than suspected and are readily diagnosed by this modality. With this mind, clinical, pathological, diagnostic and therapeutic aspects of the 71 patients with primary carcinoma of the duodenum reported in the literature in the last 10-year period, 1965-1974, were reviewed. It would appear that fiberoptic endoscopy of the upper gastro-intestinal tract should become the major diagnostic tool for this disease. It enables biopsies, brushings and washings to be taken. A preoperative histological diagnosis ensures that both patient and surgeon can be prepared for major abdominal surgery. It is imperatire that during the endoscopic examination, the entire duodenum be examined. Pancreatico-duodenectomy appears to offer the best chance of long term survival in patients whose lesion is resectable. The role and value of adjuvant chemo- and radiotherapy is still to be determined.