Introduction A moderate or often severe anemia of the normochromic normocytic type is usually present in patients with chronic renal disease. In 1950, Callen and Limarzi1 made a careful hematologic study of 102 patients with renal disorders and reviewed the literature pertinent to this anemia. They concluded (1) that there was a functional suppression of the normoblastic elements of the bone marrow in renal disease with uremia and (2) that the degree of anemia appeared to be roughly proportional to the impairment in kidney function as measured by the level of nonprotein nitrogen in serum. Kidney pathology per se without retention of nitrogenous products in the blood was not associated with anemia. Recent studies of nephrectomized animals,2-3 as well as studies of patients with uremia in whom the turnover of radioactive iron was measured,4-6 have supported these conclusions. Such studies have shown, in addition, that the anemia