The present studt was completed to assess the clinical utility of B protein, as a tumor marker of hepatocellular carcinoma. The association of B protein and liver cirrhosis was also evaluated because hepatocellular carcinoma is usually combined with cirrhosis. The serum levels of B protein were studied by a Latex-agglutination test. One hundred and twenty-nine patients including 23 hepatocellular carcinoma, 50 hepatocellular carcinoma combined with liver cirrhosis, 40 liver cirrhosis, and 16 chronic hepatitis were tested. The positive rates of B protein in various diseases were as follows: 30.4% (7/23) in patients with hepatocellular carcinoma; 68.6% (35/50) in patients with hepatocellular carcinoma combined with cirrhosis; 82.5% (33/40) in patients with cirrhosis; and 62.5% (10/16) in patients with chronic hepatitis. When B protein was used as a tumor marker of hepatocellular carcinoma, the sensitivity (57.5%) and specificity (25%) were very low. Furthermore, patients with hepatocellular carcinoma, usually combined with cirrhosis; which carried the highest positive rate on B protein determination. This also limited clinical utilization of B protein as a tumor marker of hepatocellular carcinoma. Moreover, there was no correlation of B protein with the serum alpha-fetoprotein level or tumor size. On the contrary, positive correlation of the B protein level with Child's staging (Tau-c value = 0.392, p = 0.008), and death during follow-up (Tau-c value = 0.456, p = 0.021), were discovered in patients with cirrhosis.(ABSTRACT TRUNCATED AT 250 WORDS)