Prosthetic hip replacement is associated with certain complications which result in a painful hip. Many ofthese, e.g. prosthetic dislocation, fracture, trochanteric avulsion, and heterotopic calcification are easilydiagnosed by conventinal radiography. However, radiographic evaluation for infection and/or loosening ofprosthesis as major complications requiring reoperation often contributed little to the resolution of thediaignostic problem, The authors made a comparative study of plain radiography and scintigraphy of 39 casesperformed revision at Kyung Hee University Hospital from Sep.1981 to Aug. 1986. The results were as follows: 1. In39 revised prosthetic hip replacement, 26 cases (67%) of loosening without infection and 11 cases(28%) ofinfection were proven. 2. In loosening of prosthesis, plain radiography showed true positive rate of 76% and truenegative rate of 60%, and scintigraphy showed true positive rate of 75% and true negative rate of 95%. 3. Ininfection of prosthesis, plain radiography revealed true positive rate of 55% and true negative rate of 96%, andscintigraphy revealed true positive rate of 100% and true negative rate of 83%. 4. Scintigraphy and plainradiography were useful as complementary procedure in evaluatin and differentiating loosening and/or infection ofprosthetic component.