The purpose of this study was to evaluate a new endoscopic ultrasonography (EUS) device using a curved-array transducer with a 120-degree sagittal scan angle in the diagnosis of pancreatobiliary disease. From October 1991 to June 1993, 94 patients underwent EUS to assess radiologically detected anomalies (62 cases), tumors of the papilla of Vater (seven cases) and laboratory findings demonstrating cholestasis of unexplained origin (25 cases). In 41 cases, surgery was performed after EUS, and in 40 cases ERCP was also performed. The EUS diagnosis of chronic calcifying pancreatitis was confirmed by ERCP in 14 of 18 patients. In 30 cases, EUS detected a pancreatic tumor. In 26 of these patients, surgery was performed, confirming EUS findings regarding tumor size, portal, mesenteric, and splenic invasion, and lymph-node involvement in 20 of 25 pancreatic carcinomas (80%). In five of seven patients in whom EUS detected ampullary carcinoma, cephalic duodenopancreatectomy was performed, and the histology of the surgical specimen confirmed the diagnosis in all five. In 25 patients presenting with cholestasis of unexplained origin, EUS provided the diagnosis in 22 cases (88%). EUS using a curved-array transducer appears to be an effective diagnostic method for pancreatobiliary lesions. These results should be further evaluated in a larger series of patients.