A double-blind placebo-controlled randomised clinical trial was conducted on 41 patients with non-alcoholic fatty liver disease (NAFLD). Participants were randomly allocated to receive either a cranberry supplement or a placebo for 12 weeks. Both groups were assigned to follow a weight loss diet. At the end of the study, alanine aminotransferase and insulin decreased significantly in both groups (p < .05); however, this reduction was significantly greater in the cranberry group than in the placebo group (p < .05). Significant improvements in insulin resistance were observed in the cranberry group and between the two groups (p < .001 and p = .020, respectively). Also, there was an improvement in steatosis grade and anthropometric measurements in both groups (p < .05), and there was no significant difference between the two groups in regard to these factors (p > .05). It seems that 288 mg of cranberry extract might improve managing NAFLD, which is equivalent to 26 g of dried cranberry..