ABSTRACT. Figueiredo M.A.F., Alves G.E.S., Michael A.F.M., Lima A.E., Wenceslau A.A., Ferreira M.L., Clark R.M.O. & Ayres M.C.C. [Effect of Platelet Rich Plasma therapy in the repair of experimental lesions of the suspensory ligament in horses.] Efeito do tratamento com Plasma Rico em Plaquetas sobre lesões do ligamento suspensor do boleto de equinos, induzidas experimentalmente. Revista Brasileira de Medicina Veterinária, 38(Supl.1):85-92, 2016. Departamento de Ciências Agrárias e Ambientais, Universidade Estadual de Santa Cruz. Rodovia Jorge Amado, Km 16, Salobrinho, Ilhéus, BA 45662-900, Brasil. E-mail: email@example.com The relevance of Platelet Rich Plasma (PRP) as a regenerative therapy is increasin, particularly in equine sport medicine, but there is still lack of controlled studies demonstrating its action in treating ligament injuries. This study was designed to evaluate the effect of Platelet Rich Plasma therapy in the repair of experimental injuries in equine suspensory ligament (SL). PRP was evaluated for treatment of desmites surgically induced in the body of the SL in six horses. PRP was applied 14 days after induction of the lesions, in the thoracic and pelvic left limbs; right limbs constitute control. Sonographic examinations were performed weekly to monitor the dynamics of lesions Intensity Rate (IR), based on ecogenicity and cross-sectional área. Forty-six days after PRP treatment, samples of the ligaments were collected and evaluated for celularity, vascularity and colagen content. The group treated with PRP presented reduced intensity rate (IR), improving ecogenicity in SL lesions. Treated group also presented higher neovascularity and type I colagen content. The number of fibroblasts was higher in treatment group, but it was not significant. The results suggests that PRP was effective in improving suspensory ligament repair in this study.