The authors monitored a group of 87 patients after a reoperation of the total replacement of the hip joint due to the so-called aseptic loosening of one of the components. On the basis of the evaluation of clinical complaints and an x-ray finding of the extent and progress of the so-called radioluscent line on the cement-bone interface and their correlation with the peroperative finding of the loosening of the implant they developed an x-ray classification of the loosening of the total endoprosthesis. This three-grade classification facilitates the consideration of the latest state of the fixation of the implant and the prognosis of further development. It is a therapeutical guideline for the determination of the period suitable for reoperation and possible exchange of endoprosthesis. Key words: total endoprosthesis of the hip joint, aseptic loosening, diagnostics.