Purpose - To compare in a prospective clinical study the value of sCT and rEUS for the diagnosis and staging of pancreatic and ampullary tumors. Methods - Between July 1997 and October 1999, sixty-one patients with clinical suspicion of a pancreatic or ampullary tumor underwent both sCT and rEUS. Biliary and pancreatic tumors were suspected on the presence of obstructive jaundice n=44 (72,1%), back pain-weight loss- biologic abnormalities (cholestasis-rise of pancreatic enzymes) n=11 (18,1%),and identification of pancreatic mass or biliary obstruction by transabdominal ultrasonography n=6 (9,8%). The CT scans were read by the same radiologist (MR). EUS was performed by a single investigator (FMF) using a Olympus GF-UM20 and UM-30 echoendoscopes (Olympus Co.,Tokyo, Japan). The investigators were blind to the findings of other imaging methods (except transabdominal ultrasonography). Patients underwent EUS and CT within a 7-day period. Fifty-six patients had surgical exploration. All patients had a histological diagnosis. The results of CT and EUS were compared with the operative and histological findings. Fischer's exact chi-square test was used to compare sensitivities and specificities; pvalues below.05 were considered significant.* Results - The histological diagnosis was ductal adenocarcinoma of the pancreas in 28 (45,9%)patients, ampullary adenocarcinoma in 10 (16,4%), adenocarcinoma of the bile ducts in 3 (4,9%), pancreatic cystoadenoma in 3 (4,9%), mucin-producing intraductal neoplasia in 2 (3,3%). Chronic pancreatitis, cholelithiasis and its complications accounted for the diagnosis in 8 (13,1%) and 7 (11,5%) patients, respectively.There was no difference between the methods in the diagnosis of pancreatic cancer (EUS x CT: sensitivity 96.4% x 85.7%, especificity 90.6 x 90.9, accuracy 91.8% x 88.5%). EUS was more accurate for definition of the “T” stage of pancreatic cancer (EUS x CT: 84.6% x 53.8%)*. The sensitivity and specificity of rEUS and CT for detecting lymph nodes were similar. Portal vein and superior mesenteric vein invasion and unresectability was correctly predicted by rEUS and CT in 14 (93.3%) and 9 (60.0%) of 15 patients*. rEUS demonstrated 9 and CT three of the 10 ampullary adenocarcinomas*. Conclusions - sCT and rEUS do not differ for diagnosis and “N” staging of pancreatic tumors. EUS performed better for “T” staging, prediction of unresectability of pancreatic cancer and detection of ampullary tumors.