The diagnosis of ampulla of Vater tumors is complex due to the proximity of other anatomical structures that are the originating sites of tumors with different natural histories, treatment and prognosis. A retrospective study of 65 consecutive patients with conclusive ampulla of Vater tumor diagnosis from January 1994 to April 1998 was conducted. Icterus was the principal symptom in 92%. In 34/65 patients on whom ultrasound or CT scan were performed, nearly half showed only dilation in the bile ducts, an ampullar tumor was suspected in six, in another six, pancreatic tumor was suspected and then discarded, and seven had no specific findings. Endoscopic imaging discovered the tumor in all of the cases, but the biopsy was diagnostic in only 84.6%: forty-eight carcinomas were discovered in addition to six adenomas (two with carcinoma and one with dysplasia) and one lymphoma. A diagnosis was arrived at in ten patients with negative biopsies through other means. Surgeries uncovered two carcinoids with endoscopic diagnosis of carcinoma. It was concluded that endoscopy is a good diagnostic method that allows palliation; however, it requires a perfecting process such as endoluminal ultrasound, specially if, taking into consideration the elevated morbimortality involved in pancreatoduodenectomies, conservative treatment is sought.