This paper analyzes the value of ultrasonography (US), computerized tomography (CT) and endoscopic retrograde cholangiopancreatography (ERCP) to establish the location, nature and resectability of carcinomas of the pancreatic head and of the periampullary region. The prognostic importance of certain pathological factors in relation to survival was also evaluated. As regards the site of origin, 112 cases with carcinoma were classified as follows: 56 pancreatic, 32 ampullary, 10 common bile duct, and 14 undefined. Papillary tumors were more accurately defined by ERCP compared to CT+US (p = 0.033), whereas CT was less accurate than US+ERCP (p = 0.05). No significant differences were found in pancreatic and common bile duct tumors. Pathological confirmation was obtained with ERCP in 54 cases (46% pancreatic, 69% papillary and 50% common bile duct). In the remaining 58 patients (including 1 chronic pancreatitis) the diagnosis was confirmed with percutaneous or intraoperative biopsy. Tumor extent was better defined by US+CT. In 42 resected patients the final pathological examination revealed an error of preoperative staging in 79% pancreatic, 59% papillary, and 83% common bile duct tumors. Tumor size, nodal status, perivascular, capsular and portal vein infiltration proved to be significant prognostic factors for pancreatic tumors. Stepwise regression identified tumor size, capsular infiltration and perivascular invasion as the most important covariates for survival. Ulceration, papillary histotype, pancreas and Oddi muscle infiltration, grading, perineural, lymphatic and vascular involvement were found to be significant in papillary tumors. The Cox proportional hazard model showed that pancreatic, Oddi muscle, perineural infiltration, and histologic type respectively represent a relative risk of 5.93, 107.36, 21.31, 20.61. The limited number of cases of common bile duct primary did not allow us to carry out statistical analysis on these tumors.