Aim: Non-alcoholic fatty liver disease (NAFLD) is one of the metabolic disorders related with inflammation. Nigella sativa (NS) has various chemical compounds includes thymoquinone (TQ), unsaturated fatty acids and flavonoids. NS is used as anti-inflammatory and anti-oxidant in medical science. The aim of this study was to investigate the effect of NS oil supplementation on levels of adiponectin, leptin and blood pressure in patients with non-alcoholic fatty liver. Methods: This randomized, double-blind, placebo-controlled clinical trial was performed among 44 patients diagnosed with NAFLD. Subjects were randomly assigned to placebo group (n=22) and/or intervention group (n=22), supplemented with 1g/day of NS oil. The duration of the intervention was 8 weeks. Blood samples were collected at baseline and at the end of the intervention and serum levels of adiponectin, leptin and systolic and diastolic blood pressure were measured. Results: NS oil supplementation did not have a significant effect on serum levels of adiponectin and leptin. Also, no significant effects were seen with this supplementation on systolic and diastolic blood pressure among patients with NAFLD. Conclusions: In the current trial, 8 weeks of nigella sativa oil supplementation demonstrated did no significant effects on serum levels of adiponectin, leptin and blood pressure in people with NAFLD.