Lameness in horses can have many causes. One of them is bone cysts, which often settle at the knee joint of thoroughbreds, but in warm-blooded horses and jumpers can affect various parts of the legs – often the toe joints. The cysts form cavities under the joint surface. Depending on their size, they lead to increased pressure in the adjacent bone and cause pain comparable to pain in people suffering from osteoarthritis. Cysts are quite common in horses. Reasons for their formation are either growth or circulation disorders, inflammations or hairline cracks in the bones caused by overloading. There is also a genetic predisposition to cyst formation. Cysts can be treated conservatively as well as surgically. The short lecture presents the most optimal treatment methods and the latest surgical techniques.