To evaluate the prognostic value of serum copper (S-Cu) and ceruloplasmin and their pathophysiologic significance in human hepatocellular carcinoma (HCC), we studied 49 patients with HCC (20 of which were submitted to partial hepatectomy) compared with 110 patients with liver cirrhosis. In HCC both S-Cu and ceruloplasmin were higher than in cirrhosis; moreover, S-Cu was correlated with the extension of HCC, evaluated by instrumental data and by surgical inspection. In cirrhotic patients, mean S-Cu was 122.9 micrograms/dl (SD, 29.3), in early HCC, 153.0 micrograms/dl (SD, 34.5), and in advanced HCC, 193.1 micrograms/dl (SD, 37.7). Variance analysis gave F = 59.4. In HCC patients S-Cu was positively correlated with ceruloplasmin and with fibrinogen. Survival, evaluated by Mantel's test stratified for surgical therapy, was longer in patients with S-Cu levels lower than 175 micrograms/dl and in those at an earlier stage. We therefore conclude that S-Cu has a relevant diagnostic value in detecting HCC also in early stage and allows prognostic evaluation as regards survival.