Forelimb deformity caused by radial agenesis was diagnosed in a one-year-old Shih Tzu dog. In contrast to most of the previously reported cases of radial agenesis, the humeroulnar joint was Inherently stable. The deformity was treated by means of a one-stage ulnocarpal arthrodesis with the application of an eight hole dorsolateral arthrodesis bone plate and autogenous cortlcocancellous bone graft from the iliai wing. Radiographic evaluation at the eighth and sixteenth post-operative week showed evidence of union of the arthrodesis. At sixteen weeks post-operatlvely, the dog had much improved limb function. In humans afflicted with radial agenesis, ulnocarpal arthrodesis Is used to restore forearm function by minimizing pain and decreasing the magnitude of angular deformity and instability at the level of the ulnocarpal joint. However, to our knowledge, this is the first report of treatment of radial agenesis in the dog by means of a one-stage, ulnocarpal arthrodesis. © 2007 Schattauer GmbH.