Between 1976 and 1983, 92 patients (mean age: 70 years) with ampullary or periampullary tumors, were evaluated by endoscopic procedures. The ampulla appeared malignant in 66 p. 100 of cases, enlarged but not obviously malignant in 15 p. 100 and normal in 18 p. 100. In one case, a tight duodenal stenosis prevented the endoscopist from seeing the ampulla. ERCP was performed in 70 patients and the common bile duct was opacified in 63 cases; it was dilated in 60 patients. Two types of tumors could be distinguished: 67 p. 100 grew within the duodenum and were seen by duodenoscopy and 33 p. 100 grew outside the duodenum and ERCP opacified a dilated common bile duct above a stenotic region; in these cases, diagnosis was established by biopsies performed through the ampulla, after endoscopic sphincterotomy (EST). Biopsy specimens were obtained in 67 p. 100 of cases and yielded a diagnosis of adenocarcinoma in 59 p. 100, questionable carcinoma in 15 p. 100, benign tumor in 16 p. 100 and normal mucosa in 10 p. 100. In 8 patients with the preoperative diagnosis of non-malignant tumor, operative biopsies finally revealed carcinoma in 7. EST or infundibulotomy was performed in 42 patients with 2 deaths from hemorrhage and cholangitis. Twenty-three patients received only EST as final treatment with complete disappearance of jaundice and/or cholangitis in 70 p. 100. Our results confirm the efficacy of duodenoscopy, ERCP and EST in the diagnosis and sometimes in the treatment of ampullary and periampullary tumors.