Background and Aim:Cartilagedisordersmaydeterioratefollowingoxidative stress injuriesaffectingmature chondrocytes. Meantime, mesenchymal stem cells (MSCs)candifferentiateinto chondrocytes in thepresence ofoxidative conditionsandact as asourceofcompensationforinjured chondrocytes. The present study aimed to investigate the effect of H2O2on MSCsdifferentiation into chondrocytes in order tocastlight on the dual roles of oxidative stress inthepathogenesis of diseases.Materials and Methods:Human mesenchymal stem cells were isolated from abdominaladipose tissue of three different donors and cultured in the presence of 50MH2O2in orderto differentiate into chondrocytes.We determined cell viability by tetrazolium assayandmeasuredreactive oxygen species (ROS) level by flow cytometry.Presence ofglycoseaminoglycans was confirmed by safranin staining.Results:The percentage of cells containing ROS was significantly higher inthe cells treatedwithhydrogen peroxide (29.2%1) compared tothat in theuntreated control cells (7.7%1.4). A significant increase in glycoseaminoglycan content was observed in H2O2treatedcells comparedto that in thecontrol cells both onthe9thday (treated: 1.57×104± 0.1vscontrol: 0.91×104± 0.09) and21stday (treated: 2.87×104± 0.2vscontrol: 0.96×104± 0.07).In addition,comparison of glycoseaminoglycan content on the 9thand 21stdays showed asignificantly higher content inboth treated and control cells on the21stday(p<0.05).Conclusion:Hydrogen peroxide resulted in increased differentiation of adipose tissue-derivedMSCs into chondrocytes. Therefore,weconcluded that, oxidative stresshadpositive role inthe induction ofchondrocyte differentiation.