Background: Aflatoxins are the secondary metabolites produced by the flavi section of Aspergillus. Aflatoxin B1 (AFB1) is hepatocarcinogen, teratogen and mutagen. Aflatoxin M1 (AFM1) is the hydroxylated metabolite of AFB1. The liver protects the body by lowering the toxicity of AFB1 to form different hydroxylates like AFM1. According to the synergistic effect of HEPATITIS and also AFB1 as the parent molecule of AFM1, the main purpose of this study was to assess the relationship between the mean levels of AFM1, in the HEPATITIS-C-virus (HCV) -positive patients compared to healthy individuals.Methods: After the tests of liver function enzymes, the level of AFM1 was measured and compared in the urine sample of 71 patients with HCV and 71 healthy individuals. The AFM1 of urine samples were tested using enzyme-linked immunosorbent assay (ELISA) method. Besides, the levels of serum glutamic-oxaloacetic transaminase (SGOT), serum glutamic-pyruvic transaminase (SGPT), alkaline phosphatase, total bilirubin and direct bilirubin were assessed in the blood samples.Findings: The urine of 29.7% of HCV-positive patients and 19.71% of healthy individuals consisted of some amount of AFM1. The mean level of AFM1 was 2.45 and 1.66 pg/ml in patients and controls, respectively; which was significantly different (P=0.005). The mean levels of SGPT and alkaline phosphatase were significantly more among HCV-positive patients with AFM1 compared to those without AFM1 (P=0.012). But, there was not any significant difference between the mean levels of SGOT and total and direct bilirubin between the HCV-positive patients with and without AFM1.Conclusion: The mean levels of SGPT and Alkaline phosphatase, which are more exclusive to survey of liver function, were significantly different between HCV-positive patients with and without AFM1. Consequently, progression of the chronic liver disease is caused by the existence of AFB1 in HCV-positive patients; therefore, the reduction of AFM1 via improving the food consumption pattern can prevent this progression.