Five patients in early childhood had moderate to marked anemia and clinically demonstrable thick long bones of the extremities with radiologic features of diaphyseal dysplasia. Although the anemia was persistent and not responsive to hematinics, prednisolone was administered to two of these patients and caused remarkable improvement of the anemia in both. Roentgenologic examination carried out after 1 year of corticosteroid therapy in one patient and after 11 years in another showed considerable improvement of the bony changes. The clinical and radiologic examinations of these patients and their follow-up study suggest that they may constitute an unusual group of patients with diaphyseal dysplasia associated with anemia, hitherto not well defined.