The frequent association between familial adenomatous polyposis and duodenal tumors is increasingly recognized, yet many patients do not benefit from adequate diagnosis and follow-up of upper gastrointestinal polyps. A retrospective review of 14 patients with duodenal tumors associated with familial adenomatous polyposis was undertaken to assess the impact of early diagnosis by screening asymptomatic patients. Six of eight patients presenting with symptoms suggesting duodenal disease had invasive cancer. Four of these six patients died after surviving a mean of 13 months after diagnosis. In contrast, none of the six patients diagnosed after screening with upper gastrointestinal endoscopy has had invasive carcinoma. Early diagnosis and long-term surveillance of asymptomatic patients with familial adenomatous polyposis affords the opportunity to diagnose and treat duodenal tumors at an early stage, thereby, avoiding the dismal prognosis once invasive cancer has developed.