Bone uptake of 99 m Tc diphosphonate may allow early diagnosis of renal osteodystrophy. Our study deals with 53 patients treated by repeated hemodialysis and reveals scanning abnormalities in 75% of them. Bone scanning provides information which are not visualized radiologically, especially scattered or located pulmonary calcifications (15% in our series). It is valuable in the follow-up of bone changes and is part of the necessary investigations before carrying out parathyroidectomy.