To establish the predictive value in osteodystrophy of hair aluminium content in patients on hemodialysis, we compared the aluminium levels in serum, cortical and trabecular bone and hair of 40 such patients with the levels in 23 healthy controls. In the patients, mean hair aluminium content was significantly higher than the controls (0.226 mumol/g, range: 0.09-0.500 mumol/g, n = 39 versus 0.126 mumol/g, range: 0.020-0.330 mumol/g, n = 49) but there was a large overlap between the two groups. The patients exhibited a significant correlation between serum and cortical bone aluminium measured by atomic absorption spectrometry (rs = 0.67, n = 37, p less than 0.05), but no correlation between aluminium in hair and in serum or bone, whether cortical or trabecular. Bone histomorphometric studies also indicated that unlike aluminium levels in cortical or trabecular bone, its levels in hair are not predictive of aluminium-induced osteomalacia. Consequently, hair aluminium cannot suitably replace bone and serum aluminium as a criterion of osteodystrophy in hemodialyzed patients.