Asymmetric dimethyle arginine(ADMA) has an important role in regulating NO production by acting as competitive inhibitor of all three NOS isoforms.ADMA is synthesized during the methylation of protein arginine residues by protein arginine methyltransferases (protein methylases, PRMT).The aim of this study was to evaluate plasma ADMA level in patients with chronic active hepatitis and to correlate its level with liver dysfunction.Fifty five subjects were included in this study and were classified into 15 healthy subjects as control (group I), 20 chronic active hepatitis C patients with no sonographic evidence of cirrhosis( group II) and 20 chronic active hepatitis C patients with sonographic evidence of cirrhosis (group III).Plasma ADMA level of was measured by ELISA.ج This study showed thatHepatic dysfunction is the most prominent determinant of ADMA plasma concentration.Highly significant increase in the mean plasma ADMA level in cirrhotic group as compared to both control group and non cirrhotic group. Significat correlation between plasma ADMA and serum ALT, total bilirubin and albumin.