A prospective study was made of the evolution of serum ferritin levels in 112 renal transplant recipients with good graft function. The rise in hemoglobin value is accompanied by a decrease in basal serum ferritin levels which are lowest at the sixth month: 54.9 (2–1,516) vs. 109.6 (21–4,420) μg/l, p < 0.001 (áºŠg and range). After this time, ferritin values increase, although they do not reach basal levels. Evolution after transplantation is mainly determined by the previous state of iron stores at the time of transplantation. While in the patients with high basal serum ferritin values these gradually decreased during the follow-up period, patients with low basal serum ferritin levels tend to replenish their iron stores after renal transplantation. These differences disappear at the third year when serum ferritin values are similar in all groups. An association between persistence of posttransplant anemia and low serum ferritin levels is observed. This event is not clinically relevant as anemia disappears in almost all cases and dietary iron is enough to normalize serum ferritin levels.