Despite advent of CT and ultrasound, endoscopic retrograde cholangiopancreatography (ERCP) remains useful in the preoperative evaluation of the pancreas. Using radiographic criteria previously described, ERCP was accurate in 90% of 71 patients in differentiating benign from malignant disease. Diagnostic errors were caused by chronic pancreatitis mimicking carcinoma (N=4) and carcinoma developing in a gland with chronic pancreatitis (N=3) missed on ERCP. Chronic pancreatitis was associated with a normal ERCP in 10% (N=4) of patients.