To assess the safety and potential efficacy of a standardized technique consisting of intra-articular injection of 10 cc of a homogeneous mixed product using autologous micro-fat and platelet rich plasma (PRP) (ratio 1:1) in the carpus or the fetlock joint of sport horses presenting degenerative joint disease (DJD). Eight sport horses with DJD confirmed by radiography and ultrasonography and causing lameness and the impossibility to compete were treated. PRP was prepared after a double centrifugation whereas micro-fat was harvested and purified using a closed system. The two products were connected and mixed by gentle back and forth shaking of the syringes to finally obtain 10 ml of an homogeneous mixed product. Follow up was performed from 5 to 10 months with assessment of AAEP lameness score and return to training and competition.Nine joints were treated with significant improvement of the AAEP lameness score three months after the procedure (p = 0.021). Four horses returned to official competition between 5 to 10 months after the procedure (7.0±2.5) and three of them resumed intensive training between 5 to 9 months (6.3±2.3). No adverse event occurred.This study is a first step in the development of innovative therapy for DJD which combines the potential chondrogenic differentiation of MSCs inside equine adipose tissue with the proliferative effect of growth factors present in PRP.