Osteo-arthritis is the most common degenerative joint disease. Recently, the regenerative potential of mesenchymal stem cells (MSCs) has been under intense investigation because of their ability for self renewal and differentiation to reconstitute muscle, cartilage or bone. In this study, 50 patients with mild to moderate osteo-arthritis knee were selected and divided in two groups (group A and group B). Group A received arthroscopic debridement alone and group B received buffy coat (mesenchymal stem cell concentrate) injection along with the arthroscopic debridement of the knee. On follow-up, patients were assessed on the basis of visual analogue scale (VAS) score and osteo-arthritis outcome score, to compare results in both groups against each other to determine the efficacy of arthroscopic injection of buffy coat in the management of osteo-arthritis. The results suggest that the technique used in the study considerably improved the overall osteo-arthritis outcome score, especially the quality of life within the studied follow-up period and at the end of the follow-up.