Avulsion of the insertion of the triceps tendon, which had a pre-existing tendinopathy, is described in a cat. The tendon was re-attached to the olecranon and the repair was immobilised using a type la trans-articular external skeletal fixator. The treatment was successful, however, mild and intermittent lameness persisted. Although it is an uncommon condition in small animals, the diagnosis should be based on careful clinical and radiographic examination.