Abstract: A 5 year old male, Thoroughbred horse with the left Superficial Digital Flexor Tendon (SDFT) injury was presented to veterinary center, Korea Racing Authority. The horse had been previously treated with rest, pharmacological and non-pharmacological (rehabilitation protocols) therapies without improvement. In initial physical examination, left SDFT was diagnosed with edema or swelling including lameness grade 2 and pain by an ultrasound system and veterinarian. Horse treated with autologous platelet-rich plasma into core lesion 3 times. After a 6 month follow-up, the horse has shown normal condition the left SDFT injury without lameness and pain.