We report on 2 unrelated patients with Hajdu-Cheney acroosteolysis syndrome, who had cystic kidneys with ultrasonographic changes similar to those of autosomal dominant polycystic kidney disease. Neither had a family history of Hajdu-Cheney syndrome or polycystic kidneys, nor manifestations of any other syndrome. On the basis of the findings in these 2 patients and a review of published cases, we suggest that cystic kidneys are an important component of Hajdu-Cheney syndrome.