Histochemical study of 155 bone biopsies from dialyzed patients revealed 43 cases with aluminium deposits in bone trabeculae localized along the mineralization line or in phagolysosomes of bone marrow macrophages. Aluminium was limited to macrophages in 5 cases, to mineralization line in 23 cases, and found in both localities in 15 patients. Patients with a positive finding mostly had osteomalacia (8 times) which was combined in some cases (35 times) with mild fibrous osteodystrophy. Authors failed to prove histochemically positive deposits in dialyzed patients with serious parathyroidism. Simultaneous deposits of aluminium and hemosiderin were found in the mineralization line in three patients. Bone deposition of aluminium seems to influence somehow the bone lesion but precise interpretation of the phenomenon has not been given.