We evaluated the characteristics and clinical efficacy of the“PIVKA-II IRMA‘Daiichi, ®”kit for estimating the serum PIVKA-II levels in hepatocellular carcinoma patients. Intraassay and interassay variances were within 10%. Recovery and dilution tests also gave satisfactory results. There was no significant effect of reaction time on PIVKA-II levels. However, PIVKA-II levels were significantly lower in heparinized plasma than those in serum and EDTA plasma. The cut-off level was determined as 40mAU/mL, mean +3SD of PIVKA-11 level in 84 normal control subjects. The sensitivity and specificity of“PIVKA-IIIRMA lsquo;Daiichi, ®”kit for hepatocellular carcinoma patients was 81; 6% and 82.4%, respectively. A significant correlation was observed between PIVKA-II levels measured by“PIVKA-II IRMA‘Daiichi, ®”kit and “EitestR Mono P II”EIA kit (r=979) . In conclusion, “PIV-KA-II IRMA‘Daiichi, ® kit is considered to be accurate and useful for measuring PIVKA-II levels in hepatocellular carcinoma patients.