Serum CA 242, CA 19-9 and CEA concentrations were determined in 94 subjects divided into 5 groups: Group 1 consisted of 22 healthy subjects; Group 2 consisted of 40 patients with pancreatic adenocarcinoma; according to Cubilla and Fitzgerald's classification, 11 tumours were Stage I, 4 were Stage II, and 25 were Stage III. Group 3 consisted of 10 chronic pancreatitis patients, group 4 of 10 acute pancreatitis patients, group 5 of 12 patients with nonpancreatic digestive carcinomas. Ten of these 12 patients had distant metastases. The sensitivity of CA 19-9 in the diagnosis of pancreatic cancer was higher than that of CEA and CA 242 (p < 0.05 and p < 0.005, respectively). In Stage I cancer patients the sensitivity of the markers studied was less than 50% (45% for CA 19-9, 18% for CEA, and 9% for CA 242) whereas most of the 25 patients with metastatic tumours of the pancreas had elevated serum levels of all 3 markers. The various combinations of the three markers did not significantly improve the sensitivity in diagnosing pancreatic cancer. No relationship was found between the localization of the tumour and the serum levels of the 3 markers studied. Similarly, no differences were found between patients with cholestasis and those without. The specificity of the 3 markers, evaluated in patients with benign pancreatic diseases, was 100% for CA 242, 90% for CA 199 and 70% for CEA.(ABSTRACT TRUNCATED AT 250 WORDS)