Renal transplantation is the treatment of choice for many patients with end-stage renal disease. In the donor, renal excretory function is not affected after nephrectomy; however, little is known about other functions such as erythropoietin production. We studied the erythropoietin production in renal donors after nephrectomy. We included healthy individuals fulfilling the criteria for kidney donation. Blood samples were collected before and monthly from 1 to 6 months after nephrectomy. Complete blood cell counts and erythropoietin were assayed. Eight kidney donors were studied. A significant increase in erythropoietin levels was observed during the first 3 months, but no difference was observed by the 4th month as compared with basal values. Erythropoietin production rose during the first 3 months after nephrectomy. However, erythropoietin was normal by the 4th month. Unchanged hemoglobin levels may suggest that the compensatory production of erythropoietin could participate in the preservation of an adequate physiological status of the donor after nephrectomy.