Background: Given the liver's large size, it performs many essential functions that the body needs and cannot do without. Conversely, any dysfunction in these functions can lead to a specific liver disease. To determine the type of disease, it must be diagnosed, and this diagnosis is made through several well-known tests. However, in this study, we will attempt to explore the diagnostic role of miRNA-122 in these diseases, as it can be used as a comprehensive, definitive diagnostic tool. 
Subjects and Methods: One hundred samples were collected from patients with liver disease and 100 samples from healthy individuals for comparison. The mean ages of the patients and controls ranged from 52.12 ± 12.470 to 49.23 ± 13.465, respectively. Five milliliters of blood were drawn from all participants, and 1 ml of each sample was used for real time polymerase chain reaction (RT qPCR) analysis to detect miRNA 122. Remaining amount of each sample was used to measure interleukin-18 using enzyme-linked immunosorbent assay (ELISA), in addition to other biochemical tests performed in this study. 
Results: Regarding the amount of miRNA-122, the results showed statistical significance between the two groups (P < 0.05). Patients' serum levels of interleukin-18 were higher than those of the healthy group (P = 0.001). Statistical differences were clear and significant between the two groups in all other biochemical tests (P < 0.001). 
Conclusions: In conclusion, the results showed that miR-122 is closely associated with various liver diseases, demonstrating its potential as a definitive diagnostic tool in this regard.