PIVKA-II (protein induced vitamin K absence or antagonist-II) levels in plasma were measured using ELISA in patients with hepatocellular carcinoma (HCC). PIVKA-II was detected in 53 of 97 patients (54.6%) of HCC, and the combination assay of PIVKA-II and AFP identified 69 of 97 patients (71.1%) with HCC. However, the positive rate of PIVKA-II (6.1%) was lower than that of AFP (37.5%) in patients with HCC less than 2 cm in diameter. The concentration of PIVKA-II was markedly reduced within 2 weeks after treatment in patients with HCC showing a favorable response to Lp-TAE or Lp-TAI. Although PIVKA-II is a valuable marker for the diagnosis and follow-up of patients with HCC, it must be noted that the change to negative concentration of PIVKA-II after treatment does not mean complete necrosis of the tumor.