The objective of this study was to clarify the relationship between the serum level of the Lens culinaris agglutinin A-reactive fraction of alpha-fetoprotein (AFP-L3) and the clinical features including sex, age, Child's classification, virus markers, tumour size, tumour stage, distant metastasis, histopathologic findings, portal thrombus and outcome of hepatocellular carcinoma (HCC). We measured the AFP-L3 levels in 170 HCC cases at the time of diagnosis using lectin-affinity electrophoresis followed by antibody-affinity blotting. The patients were divided into two groups, those who were AFP-L3 positive (n=56; AFP-L3 >/=15% relative to the total alpha-fetoprotein (AFP) concentration) and those who were AFP-L3 negative (n=114; AFP-L3 <15%). Then we examined the association between the serum AFP-L3 level and the clinical features of HCC. No significant differences were found in age, sex, and virus markers between the AFP-L3-positive and -negative groups. However, patients in the positive group had worse liver function and larger tumours compared to the negative group. They also had more advanced cancer with poor tumour histology compared to the negative group. Distant metastasis was diagnosed significantly more often in the positive group than that in the negative group. There was no significant correlation between the AFP-L3 level and portal thrombus. Although the follow-up period was brief the prognosis for the positive group clearly was poor. These results suggest that AFP-L3 is a useful indicator of distant metastasis and a poor prognosis for HCC.