Hemodialysis induced osteopenia represents one of the serious late complications of long-term treatment with hemodialysis. The incidence of osteopenia in our hemodialysis-patients ranges between 5 and 10 percent (Atkinson et al. 1973; Delling et al. 1976; Heidler et al. 1976; Parfitt 1976; Fuchs et al. 1977a; Henning et al. 1977; Schulz 1978, 1979; Madsen 1979; Schulz et al. 1980, 1981). Well timed variation of the conventional electrolytecomposition of dialysate can prevent osteopenia in many cases successfully. Precise histological classification of bone (histomorphometrical evaluation of bone-biopsy) and determination of parathormon- and fluor-level are the obligatoric precondition of adequate osteopenia-treatment. Therapy of osteopenia comprises--beside decrease of dialysate calcium and -magnesium--stepwise increase of NaF--and 1,25(OH)2D3-application. Surveillance during therapy should include monitoring of calcium, phosphate and fluor-metabolism, microradioscopy of hand skeleton, rebiopsy of bone (iliac crest) and determination of iPTH.