A method which measures the temporal and distance factors has been employed to monitor the gait of patients one week prior to total hip replacement and six and twelve months after operation. Variables have been selected which reflect gait symmetry and others which slow the speed of walking and how this is achieved. The method of presentation of results is discussed with particular attention to the use of these results in monitoring the progress of the patient. As a group these patients showed the greatest improvement of six months after operation with little added improvement shown at twelve months.