Serum levels of laminin and type IV collagen of 188 patients with different types of viral hepatitis were determined by RIA. Thirty-five blood donors were served as normal control. The results showed that: (1) higher levels of type IV collagen was found in patients with severe chronic hepatitis, post-hepatitis cirrhosis or subfulminant hepatitis; (2) the level of laminin was obviously increased in post-hepatitis cirrhosis and subfulminant hepatitis; (3) there was a positive correlation between the levels of type IV collagen and laminin as well as gamma globulin, and negatively correlated to serum albumin, no correlation with alanine aminotransferase was observed; (4) detecting rate of hepatic fibrosis was increased with combination of serum laminin and type IV collagen examination; (5) serum type IV collagen was more sensitive than that of serum laminin. The results suggest that determination of serum type IV collagen and laminin are useful in diagnosis of hepatic fibrosis, and combination of the two parameters is recommended.