MicroRNAs (miRNAs) are small non-coding RNA molecules, which have an important function in regulating RNA stability and gene expression. They also can circulate in a cell-free form in the blood thatmakes them potential disease markers. The liver contains various classes of miRNAs in which miR-122 accounts for about 70% of all miRNAs and it has been proved that its level increases in case of liver damage. Here, we investigated plasma levels of miR-122 as a useful disease parameter in patients with chronic hepatitis C (CHC) infection. Thirty five hemophilia and thalassemia patients with CHC were studied. The total RNA was extracted from plasma samples, and miR-122 levels were measured by qPCR and then compared with the specific liver markers. The plasma levels of alanine transaminase (ALT) and aspartate transaminase(AST) were correlated with plasma miR-122 level in CHC patients, and the level of circulating miR-122 in healthy individual groups were rarely lower than those of patients with CHC. In our study, miR-122 levels correlated well with markers of liver inflammatory activity. Plasma miR-122 can be assumed to be another marker in liver similar to the currently used specific markers such as ALT and AST for evaluation of liver damage in hepatitis C virus (HCV) infected patients. Moreover, the correlation between miR-122 and ALT was shown to be higher than between miR-122 and AST.