The clinical, biochemical and radiological data of 25 patients with carcinoma of the head of the pancreas were compared with the same parameters of 25 patients with chronic pancreatitis producing cholestasis. History of alcohol abuse, pruritus and palpable gallbladder were the only clinical findings useful for the differential diagnosis. Plasma bilirubin levels were significantly higher in patients with malignancy (20.0 +/- 14.3 vs 2.5 +/- 2.4) but the course of the bilirubinemia was similar in the two groups after hospital admission. Preoperative ultrasound and cholangiography were usefull in differentiating both groups of patients. Sensibility of a point score based on significant differences was 100% for pancreatitis and 96% for malignancy.