We examined the involvement of src-related tyrosine kinases (RTK) in various human liver diseases, such as chronic hepatitis (CH), liver cirrhosis (LC) and hepatocellular carcinoma (HCC), by Western blot and immunohistochemical analysis using an anti-src-RTK polyclonal antibody (α-416). Our results showed that src-RTK were rarely found in the liver tissues from CH patients, while they were found at high amounts in those from LC and HCC patients. In addition, src-RTK were expressed more strongly in HCC than in LC. These results indicate that src-RTK may play important roles in the occurrence and development of LC and HCC.