It has been documented that chronic hepatitis may progress to cirrhosis and then develop hepatocellular carcinoma (HCC). To test whether abnormal cellular DNA increases along this line of development, liver tissues from 48 patients with chronic hepatitis, 17 with cirrhosis, and 8 with HCC were investigated for cellular DNA content with a scanning microdensitometer. Seven of 8 HCCs and 2 cirrhotic livers adjacent to HCC had abnormally increased cellular DNA content. Only 4 livers from patients with chronic liver diseases other than HCC had abnormal cellular DNA content. The cellular DNA content in livers not accompanying HCC was not related to the patient's age, histological diagnosis, and hepatitis inflammatory activity. The results confirmed the increase of cellular DNA content in HCC, but did not provide evidence of a progressively increasing DNA content from chronic hepatitis to liver cirrhosis. However, cirrhotic livers with abnormal hepatocytic DNA content deserve careful follow-up for the early detection of HCC.