Technetium-99m-polyphosphate bone scintigraphy was performed in 105 kidney-transplanted patients. The pathological scintigraphic changes were classified as either (1) generalized, symmetrical or (2) focal accumulations of the tracer in the bones. 40 of the patients had normal scintigrams. 18 patients had generalized symmetrical scintigraphic changes alone, while focal scintigraphic changes were found in 14 patients without generalized changes and 33 patients had generalized as well as focal changes. The severity of the scintigraphic findings correlated to the results of the transplantation, i.e. the total dose of prednisone, the number of rejection episodes and the creatinine clearance at the time of scintigraphy. Compared to patients on hemodialysis a less frequent appearance of generalized scintigraphic changes was found in kidney-transplanted patients, suggesting that the frequency of renal osteodystrophy decreases after a successful transplantation. The more frequent appearance of focal changes after a kidney transplantation suggests that a bone disease of a different etiology now is superimposed. As both types of scintigraphic changes showed highly significant correlations to the total dose of prednisone, it is concluded that glucocorticoid treatment is an important etiological factor in the development of focal bone lesions and may contribute to the maintenance of generalized skeletal lesions after a kidney transplantation.