Abstract Mesenchymal stem cells (MSCs) and conditioned medium (MSC CM) are now considered to be a good source for the development of regenerative medicine. Previously, we reported that tonsil-derived MSC (T-MSC) CM produces visceral fat reducing effects. As reduction in visceral adiposity is closely related to the increase of adiponectin in circulation, we sought to extend our previous findings and explore the effects of T-MSC CM on adiponectin production. T-MSC CM was collected from previously isolated and characterized T-MSCs and injected into a senescence-accelerated mouse prone 6 (SAMP6), which exhibits characteristics of aging and obesity. We observed reduction of mouse weight and epididymal adipose tissue (eAT) mass following injection of T-MSC CM. Significant increase in adiponectin expression in eAT and total and high molecular weight (HMW) adiponectin in circulation were determined in the T-MSC CM-injected mice compared to the control. In 3T3-L1 adipocytes, T-MSC CM treatment increased adiponectin secretion and multimerization. Furthermore, glucose oxidase was used to induce oxidative stress in 3T3-L1 adipocytes and effects of T-MSC CM on the reduction of reactive oxygen species (ROS) production and oxidative stress markers expression were observed. Restoration in the HMW adiponectin production was also shown which suggests that T-MSC CM may enhance adiponectin multimerization via amelioration in the oxidative stress. Further studies are guaranteed in a purpose of elucidation of anti-oxidants secreted from T-MSCs and these findings highlight the potential therapeutic relevance of T-MSC CM for treatment of obesity or obesity-related diseases. (NRF-2016R1A6A3A11933360)