We assessed the value of several serologic markers in detecting pancreatic carcinoma in a prospective study of 270 patients. The sensitivity and specificity of galactosyltransferase isoenzyme II (GT-II), carcinoembryonic antigen (CEA), alpha-fetoprotein, ferritin, C1q binding, and ribonuclease were determined. GT-II was the most sensitive (67.2 per cent) and specific (98.2 per cent) for discriminating between benign and malignant disease and was more sensitive and specific than CEA, the next most useful marker. Sensitivity was 64 per cent for ultrasound, 79.4 per cent for computerized body tomography (CBT), and 92.8 per cent for endoscopic retrograde cholangiopancreatography (ERCP). As a single test, only ERCP was more sensitive than GT-II, but more sensitive diagnoses resulted when GT-II was combined with ultrasound (92 per cent), CBT (88 per cent), or ERCP (100 per cent). Serum GT-II may be useful both by itself and in combination with imaging techniques in distinguishing benign from malignant pancreatic disease; however, this test does not discriminate between pancreatic carcinoma and other gastrointestinal neoplasms.