Previous studies have demonstrated that plasma tissue plasminogen activator (t-PA) level was elevated in patients with liver disease. In this study, t-PA antigen levels were investigated in patients with acute hepatitis (AH; N = 12), chronic hepatitis (CH; N = 8), compensated liver cirrhosis (CLC; N = 40), decompensated liver cirrhosis (DLC; N = 23) and hepatocellular carcinoma (HCC; N = 35). The increased t-PA levels (higher than 14 ng/ml) were found in 33% (4/12) of AH on the early hospital days, 25% (2/8) of CH, 45% (18/40) of CLC and 91% (21/23) of DLC, and 60% (21/35) of Hcc cases. In patient with LC, the correlations between t-PA levels and serum total bilirubin (T.Bill) and hepatic synthetic functions were investigated. The results were that the t-PA levels correlated positively with T. Bil and negatively with liver synthetic functions such as albumin, protein C and choline-esterase, indicating that t-PA increased almost in proportion to the deterioration of hepatic function. Serial determination of t-PA in patients with HCC treated by transcatheter arterial embolization (TAE) revealed that TAE failed to normalize the t-PA levels. In one case of HCC complicated with disseminated intravascular coagulation (DIC), t-PA showed a marked increase at acute phase of DIC and subsequent decrease after the successful treatment for DIC by gabexate mesilate (FOY) infusion. These results suggest that increased t-PA in liver disease is due mainly to deterioration of hepatic function, and that secondary fibrinolytic state, such as DIC, is also a contributing factor.