Serum ferritin is often elevated in patients with hepatocellular carcinoma (HCC). Its use as a disease marker has been proposed. We have measured serum ferritin levels in 85 patients with HCC and in 62 comparable subjects with cirrhosis. Abnormal values (greater than or equal to 300 ng/ml) were found in 54% of the patients with HCC and in 35% of those with cirrhosis (median 323 and 204 ng/ml, respectively). The overlap of the range of concentration in HCC and cirrhosis was so great that no discriminant level could be chosen. No relationship was found between alpha-fetoprotein and ferritin concentrations. Among 61 patients who received Adriamycin treatment, no discernible fall in ferritin levels was observed, while alpha-fetoprotein increased progressively during the follow-up. Serum ferritin has no role in diagnosing and/or monitoring the response to treatment of patients with HCC.