The purpose of the present paper is to investigate the walking pattern of patients with hip disorders. The materials consist of 37 cases of osteoarthritis, ten cases of fused hips and two cases of congenital hip dislocation which had not been treated. Of the 37 cases with osteoarthritis, seven cases were in pre-arthrosis or in the early stage of it. They had slight hip pain and an almost normal range of motion. Thirty cases were in advanced arthrosis and were treated by total hip replacement. For the purpose of examining the walking pattern of the above mentioned patients, three-dimensional components of the floor reaction force were measured by Matake's force plate, and three loop diagrams were made by taking two dimensions at a time and plotting them on an X-Y recorder in order to easily understand the walking as a pattern. In the present paper only the alpha-diagram, which is composed of the vertical, forward and backward components, was used. In the patients with osteoarthritis, the figure of the alpha-diagram decreases and the unweighting effect in the vertical floor reaction disappears as the degree of the hip pain increases, while, on the normal side, some compensatory function was seen in the characteristic figure. In the cases of untreated congenital hip dislocation, the figures of the alpha-diagram were similar to the pattern of a painful hip with osteoarthritis. From these facts it is concluded that the most important factor influencing the walking pattern is hip pain.