Histidine-rich glycoprotein is a 3.8s alpha 2-glycoprotein of human plasma originally isolated in 1972 [1,2]. The biologic function of histidine-rich glycoprotein, however, is unknown. A recent report suggests that histidine-rich glycoprotein binds to the high-affinity lysine-binding sites of plasminogen and that histidine-rich glycoprotein may retard fibrinolysis by interfering with the binding of plasminogen to fibrin [3]. We have measured the plasma titers of histidine-rich glycoprotein in normal subjects and patients with advanced hepatic cirrhosis by single radial immunodiffusion with a monospecific antiserum. The levels in 22 patients were 7.0 +/- 2.5 mg/dl (mean +/- SD), whereas those in 20 control subjects were 11.8 +/- 2.7 (p less than 0.001). Upon two-dimensional crossed immunoelectrophoresis, the pattern of histidine-rich glycoprotein in liver cirrhosis was similar to that of normal histidine-rich glycoprotein. Since histidine-rich glycoprotein seems to function as an antifibrinolytic agent, the decreased titers in cirrhosis may be one factor contributing to the enhanced fibrinolysis commonly seen in this disorder.