This study was carried out to evaluated the role of the fibronectin (FN) in chronic liver diseases. For these reasons FN plasmatic concentration was assayed in patient with different degrees of chronic liver disease. For these reasons FN plasmatic concentration was assayed in patient with different degrees of chronic liver disease; the correlation between FN and the most common parameters of liver function was also evaluated. Moreover we also correlated FN plasma levels with laminin and the N-terminale peptide of type III procollagen, serum levels, that are through to be markers of fibrogenesis. 172 patients were studied: twenty-one patients suffering from chronic persistent hepatitis (CPH), 45 from chronic active hepatitis (CAH) and 106 from liver cirrhosis (LC). Last patients were also divided according the Child-Pugh's classification. Control group was composed of 74 healthy blood donors. Significant reduction of plasmatic levels of FN was found in the LC groups in comparison with control group (p < 0.0001) and also with CPH group (p < 0.01) and with CAH group (p < 0.0001). Lower values of FN were found in the LC group at advanced stage (Child-Pugh's B and C classes). In the group of CAH significant correlations with the parameters of cholestasis (GGT, APh, Tot. Bil. p < 0.005) were found, while in the group of LC significant correlations both with the parameters of synthesis (Alb. and Protr. time p < 0.01) and necrosis (AST/ALT p < 0.001). A negative correlation was also found between FN and spleen volume (p < 0.05). No correlation between FN and the parameters of fibrosis was found.(ABSTRACT TRUNCATED AT 250 WORDS)