Over the past four decades, total hip replacement (THR) has become a well-established and largely successful procedure in dogs. More recently, the available inventory has opened up THR as an option in small breed dogs and cats. The most common indication is osteoarthritis (OA) secondary to hip dysplasia, and other candidate conditions include avascular necrosis of the femoral head, fractures of the femoral head and neck, and recurrent hip luxation. This lecture explores the indications for THR, alternative treatment options, and the advantages and disadvantages of each of these. A big part of this will be how to identify the “non-responder”: the OA patient that does not improve satisfactorily in response to medical management. The lecture should provide a greater depth of understanding of the factors used to determine whether a patient is a good candidate for THR.