A series of 40 patients were studied, who were operated upon for a painful total hip prosthesis, half of which were infected. In each case, preoperative scintigraphy was performed using Tc99, Ga67 and In111. The images obtained with Tc and Ga were compared with those of In111 and analysed with respect to sensitivity, specificity, accuracy and the predictive value of a positive or negative test. In111 had a predictive value of more than 90% and showed greater reliability in the diagnosis of an infection as the cause of a painful total hip prosthesis.