Seven patients with chronic renal failure developed a peculiar abnormality of the fingers referred to as pseudoclubbing. All had radiological evidence of severe secondary hyperparathyroidism and elevated parathormone levels measured by C-terminal assay. Treatment with vitamin D and calcium, parathyroidectomy or renal transplantation resulted in radiological healing but the deformity of the finger tips did not improve. Although these patients represent a group with severe secondary hyperparathyroidism, autonomous secretion of parathormone is not a necessary accompaniment of this disorder.