 Inclusion Criteria: - -Receiving hemodialysis for at least 6 months before screening - -Clinically stable as judged by the investigator - Stable IV rHuEPO therapy administered 1, 2 or 3 times per week for at least 8 weeks before screening stable is defined as less than or equal to 25 change up or down in weekly dose and no change in frequency over 8 weeks - Adequate iron stores serum ferritin greater than or equal to 100μgL during the screening period - Available for follow up assessments - Before any study specific procedure is carried out, the subject, or hisher legally acceptable representative must give informed consent for participation in the study Exclusion Criteria: - -Treatment for grand mal epilepsy in the last 6 months - Congestive heart failure New York Heart Association NYHA class III or IV- - Uncontrolled hypertension, defined as a predialysis diastolic blood pressure measurement greater than or equal to 110mmHg during the screening period - Clinical evidence of current uncontrolled hyperparathyroidism e.g., serum parathyroid hormone greater than 1500pgmL within the past 12 months - Major surgery within 3 months before screening excludes vascular access surgery - Previously diagnosed HIV or chronic hepatitis B infection - Clinical evidence of current malignancy excluding basal cell or squamous cell carcinoma of the skin - Systemic hematological disease e.g., sickle cell anemia, myelodysplastic syndromes, hematological malignancy; myeloma; hemolytic anemia - Alanine transaminase ALT and aspartate transaminase AST greater than 2 times the upper limit of the normal range - RBC transfusions within 12 weeks before screening or during the screeningbaseline period, or active bleeding - Clinical evidence of current systemic infections - Androgen therapy within 12 weeks before screening - No prior treatment with darbepoetin alfa - Currently enrolled in, or has not yet completed a period of at least 30 days since ending, other investigational device or drug trials. Subjects receiving other investigational agents may only enter the study after discussion and agreement with Amgen - Pregnancy women of child-bearing potential must be using adequate contraception - Breast feeding - Psychiatric, addictive, or other disorder that compromises ability to give truly informed consent or is likely to alter compliance - Anticipating or scheduled for a living-related kidney transplant 