Increased plasma levels of matrix metalloproteinase (MMP)-9 have been shown in cancerous diseases including hepatocellular carcinoma (HCC). Our present aim was to examine whether the measurement of plasma MMP-9 concentration is clinically useful for assessing or monitoring HCC patients. We measured the plasma MMP-9 concentrations in 47 HCC patients, and compared the results with the clinicopathologic features. The plasma MMP-9 levels in patients with HCC were significantly higher than those in the normal controls. The plasma levels of MMP-9 were not related to the size of HCC tumor, the grade of histological differentiation and the serum alpha-fetoprotein level. The plasma levels of MMP-9 were not significantly changed after the effective treatment of HCC tumors. In conclusion, the plasma MMP-9 test was of little value for assessing or monitoring HCC patients.