Hemophilia B (Rhodesian ridgeback type) is an inherited bleeding disorder affecting dogs. Hemophilia B (Rhodesian ridgeback type) is caused by a deficiency of coagulation factor IX, an essential protein needed for normal blood clotting. There is variation between breeds in the severity of the bleeding tendency with this disease. More severely affected dogs present with severe bleeding after minor surgeries or trauma and occasionally exhibit spontaneous bleeding. Affected dogs may also bruise easily, have frequent nosebleeds, bleed from the mouth when juvenile teeth are lost, or show signs of lameness or stiffness if bleeding occurs in the joints or muscle. A mildly affected dog may present with easy and excessive bruising and frequent nosebleeds. There is significant risk for prolonged bleeding after surgery or trauma, and in some cases, the bleeding may be severe enough to cause death. Veterinarians performing surgery on known affected dogs should have ready access to blood banked for transfusions. Most dogs will have a normal lifespan with this condition despite increased blood clotting times.