Background and aim <p>Probiotics play an important role in the control and treatment of non-alcoholic fatty liver disease (NAFLD). Kefir drink is a fermented beverage and has indicated some beneficial health effects. The aim of this study was to evaluate the effects of kefir drink on liver aminotransferases, anthropometric indices, glycemic index, lipid profile, blood pressure (BP), high sensitivity C-reactive protein, and malondialdehyde in patients with NAFLD.</p> Methods <p>In an 8-week randomized clinical trial, 80 patients with NAFLD were randomized into two groups of 40. After a 2-week run-in period, the groups received a dietary plan and dietary plan plus a cup of kefir drink twice a day (500&#xa0;cc/d), respectively. Also, demographic, anthropometric, laboratory, BP, dietary intake, and physical activity assessments were analyzed before and after the intervention.</p> Results <p>At last, seventy-two participants completed the study. No significant difference in changes in BP, anthropometric indices, and laboratory data (<i>P</i> &gt; 0.05) except HDL-C (<i>P</i> = 0.02) and fat-free mass (<i>P</i> &lt; 0.001) was observed between the two study groups.</p> Conclusion <p>Based on the results, Drinking 500&#xa0;cc/d kefir beverage had no significant effect on liver aminotransferases and metabolic indicators, except for HDL-C and fat-free mass in patients with NAFLD.</p> Trial registration <p>IRCT20170916036204N6 (2018/08/03).</p>