Therapeutic use of extracorporeal shock wave therapy (ESWT) was first reported for the treatment of uroliths in humans in the 1970s and has been used in human orthopedics for over 10 years. ESWT has had promising results treating a wide variety of musculoskeletal diseases resulting in bone remodeling, neovascularization of bone-tendon interfaces, and orthopedic pain relief. ESWT has been applied to musculoskeletal diseases in animals in the United States for over 7 years. Although, ESWT has been used extensively in human and veterinary medicine, questions regarding efficacy and mechanism of action remain. Osteoarthritis is a significant cause of lameness in humans and animals. Interestingly, studies evaluating the ESWT for osteoarthritis are lacking in literature and further trials are necessary. In Chapter 3, we have evaluated the effect of ESWT on naturally occurring osteoarthritis in the stifle joints of dogs. Analgesia has recently been identified as a potential side effect of ESWT. There are no studies that objectively evaluate analgesia following ESWT. In Chapter 4, we have evaluated the analgesic effect analgesic effect of ESWT in horses. There remains much to be learned about ESWT, as it becomes a widely accepted treatment for musculoskeletal disorders. This manuscript explores the efficacy of ESWT on osteoarthritis and characterizes post treatment analgesia effects.