A retrospective review of the medical records of 30 patients with familial adenomatous polyposis who underwent oesophagogastroduodenoscopy was performed to evaluate the spectrum of gastroduodenal polyps. Twenty-five patients (83%) had gastroduodenal polyps. Eighteen patients (60%) had gastric polyps and 21 patients (70%) had duodenal polyps. Five patients (17%) had gastric and 20 patients (67%) had duodenal adenomatous polyps. Three patients (10%) died from an upper gastrointestinal tract adenocarcinoma. Three of nine patients with periampullary adenomas had a normal-appearing papilla of Vater. Since gastroduodenal polyps are common in familial adenomatous polyposis, oesophagogastroduodenoscopy should be performed at the time of diagnosis. Biopsy of polyps as well as biopsy of a normal-appearing papilla of Vater should be performed. Due to their malignant potential, if identified, gastroduodenal adenomatous polyps should be destroyed.