In a series of 48 cases of infected hip prosthesis the different therapeutic possibilities are being discussed. In 30 instances a one stage exchange operation with the use of antibiotic bone cement as described by BUCHHOLZ was performed. Provided good stability of the new prosthesis is obtained, the signs of infection as well as most pathologic X-ray aspects will disappear, in spite of the introduction of additional implant material. After an observation time of up to 5 years more than half of the cases appeared clinically healed. The poor results generally manifest themselves within the first postoperative year. As palliation against infection a good general condition of the patient, the absence of infectious foci as well as a good operative technique and discipline to us seem more important than the number of germs in the operation theater.