A 6 month-old male Labrador retriever was presented for intermittent lameness on the left forelimb after exercise. The dog was suffering progressive lameness that had started two months before. On mediolateral radiographic view of the left elbow, proximal margin of the anconeal process was irregular. A lucent, indistinct line separating the anconeal process from the ulna was observed, when the elbow joint was flexed. The lateral approach to the elbow joint was used and the ununited anconeal process was removed. The limb was bandaged after surgery for 7 days to support soft tissue and exercises were restricted. The dog showed normal limb function 3 weeks after surgery. On a telephone conversation with the owner 18 months after surgery, the dog was reported to maintain normal function of the limb.