The aim of the study was to determine the effects of coenzyme Q10 supplementation on plasma adiponectin, interleukin (IL)-6, and tumor necrosis factor (TNF)-α levels in sedentary men. Fourteen healthy, nonsmoking, sedentary men participated in the study. The protocol was approved by the Ethical Committee of our institution. This study was a randomized, double-blind, crossover trial. Blood samples were collected from all participants before coenzyme Q10 or placebo supplementation. The participants were randomly allocated to two groups. Seven participants received oral coenzyme Q10 (100mg/day) supplementation, and seven participants received placebo (glucose) for 8 weeks. At the end of the 8 weeks, a second blood sampling was performed. After a 4-week washout period, placebo was given to the participants who used coenzyme Q10 the first time, and vice versa, and blood sampling was repeated. Plasma was stored at -80°C until the time of analysis for adiponectin, IL-6, and TNF-α. Both CoQ10 and placebo supplementation did not affect plasma adiponectin and TNF-α levels. IL-6 level increased with coenzyme Q10 supplementation, but this increase did not differ from that seen with placebo supplementation. Coenzyme Q10 supplementation did not affect plasma adiponectin, IL-6, and TNF-α levels in sedentary men. © Mary Ann Liebert, Inc. and Korean Society of Food Science and Nutrition 2010.