Background: Serum asialoglycoproteins concentration are increased in patients with hepatic disease. We developed an antibody-lectin sandwich assay that is sensitive and specific to measure asialo-α1-acid glycoprotein (AsAGP) concentration in human serum and evaluated it as a biochemical marker for hepatic disease. Methods: Serum AsAGP concentration was measured by antibody-lectin sandwich assay with 610 serum specimens of patients with hepatic disease. Serum from 41 healthy donors and 155 patients with non-hepatic disease served as negative controls. The AsAGP values were analyzed by receiver operator characteristics (ROC) curve analysis. The diagnostic accuracy of AsAGP value was compared with those of the conventional biochemical markers in the liver function test. Results: Serum AsAGP concentration in 83% of patients with liver cirrhosis (LC) and 89% of patients with hepatocellular carcinoma (HCC) was increased over the cutoff value (1.33 μg/ml), indicating that an increase of serum AsAGP concentration is restricted to LC or HCC cases. The area under curve (AUC) in the ROC curve was 0.919 for LC and 0.946 for HCC. Conclusions: Serum AsAGP concentration exhibited good diagnostic accuracy as a biochemical marker for LC and HCC. The addition of AsAGP to conventional liver function tests may significantly improve the diagnosis and prognosis.