A Mississippi kite (Ictinia mississippiensis) was presented to the Wildlife Hospital of Louisiana, School of Veterinary Medicine, Louisiana State University, for an inability to fly and was subsequently diagnosed with a minimally displaced, closed, simple, short oblique, diaphyseal fracture of the distal third of the right ulna. A figure-8 bandage was initially applied to the wing to stabilize the fracture. Over a 5-week period, the kite developed progressive reduction in wing extension, and serial radiographs revealed a bridging callus at the ulnar fracture site, as well as development of a radioulnar synostosis. To restore wing function and extension, surgical excision of the bony union between the radius and the ulna was performed, after which a polypropylene mesh implant was interposed between the 2 bones. Within 2 weeks after the surgical procedure, the kite had recovered normal wing extension and was able to fly without noticeable impairment. The bird was released 2 weeks after surgery. This case illustrates a common complication of external coaptation used as sole means of managing fractures of the avian ulna, radius, or both, which results from lack of interosseous soft tissue in the antebrachial area. On the basis of the successful outcome in this case, surgical excision of the interdiaphyseal callus and interposition of a polypropylene mesh could be a viable option for management of posttraumatic radioulnar synostosis in birds of prey.