The liver is the major source of circulating insulin-like growth factor binding protein-3 (IGFBP-3). Because the hepatic tissue is deranged in cirrhotic patients, we measured serum IGFBP-3 concentrations by two-site immunoradiometric assay in sera from 37 cirrhotic patients with different stages of hepatic dysfunction. These were compared with IGFBP-3 levels from 11 healthy controls. Serum IGFBP-3 levels in patients with chronic liver disease were significantly lower than those of the control group (P < 0.0005). The mean percent decrease in cases of early liver cirrhosis, cirrhosis without, and cirrhosis with ascites were 44%, 59%, and 82% respectively, indicating that serum IGFBP-3 levels decrease as the severity of hepatic dysfunction increases. Moreover, the decrease was more pronounced in cases with hyperbilirubinemia, elevated serum transaminases, hypoalbuminemia, and prolonged prothrombin time. There was a significant positive correlation between serum IGFBP-3 and serum albumin, as well as a significant negative correlation between serum IGFBP-3 and prothrombin time. These results indicate the close correlation of IGFBP-3 levels to worsening of hepatic functions. The determination of serum IGFBP-3 level is a clinically useful marker for the assessment of the synthetic capacity of hepatocytes in cirrhotic patients and an early predictor of impending hepatic dysfunction as well.