Five hundred examinations, including 191 esophagoscopic and 182 duodenoscopic examinations were performed on 421 patients with fiberoptic endoscopes. Diagnoses determined by X-ray and gastroscopic examination were compared and the fibergastroscope was shown to be superior in the demonstration of gastric ulcers. We feel that the fiberendoscopic examination of the upper gastrointestinal tract complements and extends the information gained from radiologic examination.