HISTORY: Suspensory ligament injury associated with avulsion or crescent fracture of third metacarpal or metatarsal bone is a common injury in racehorses. Lameness is known to be the most common clinical sign of these horses. CLINICAL FINDING: The present article investigated two avulsion fractures in the third metacarpal bone in 2.5-year-old mare and stallion, which had chronic lameness with a vague origin and disability of weight bearing in left forelimbs. DIAGNOSTIC TESTS: Following radiography and ultrasonography examinations, suspensory ligament injury and subsequently avulsion fracture in the proximal third of metacarpal bones in left forelimb were approved. FINAL EVALUATION: In radiography, radiolucent lines associated with fragmented segments (about 2×6×8 mm) in mare and (about 2×4×6 mm) in stallion  in the proximal part of  the third metacarpal bone were indicative of an avulsion or crescent fracture at the origin of the suspensory ligament. Furthermore, in ultrasonography compatible with radiographic findings, an echogenic-fragmented fracture in the proximal part of the third metacarpal bone and a local area of decreased echogenicity was diagnosed as desmopathy of suspensory ligament.