Quality of life (QOL) is markedly impaired in patients with anemia, diabetes mellitus, and chronic kidney disease. Limited data exist regarding the effect of anemia treatment on patient perceptions. The objectives were to determine the longitudinal impact of anemia treatment on quality of life in patients with diabetes and chronic kidney disease and to determine the predictors of baseline and change in QOL. In a large, double blind study, patients with type 2 diabetes mellitus, nondialysis chronic kidney disease (estimated GFR, 20 to 60 ml/min per 1.73 m(2)), and anemia (hemoglobin 10.4 g/dl) were randomized to darbepoetin alfa or placebo. QOL was measured with Functional Assessment of Cancer Therapy-Fatigue, Short Form-36, and EuroQol scores over 97 weeks. Patients randomized to darbepoetin alfa reported significant improvements compared with placebo patients in Functional Assessment of Cancer Therapy-Fatigue, and EuroQol scores visual analog scores, persisting through 97 weeks. No consistent differences in Short Form-36 were noted. Consistent predictors of worse change scores include lower activity level, older age, pulmonary disease, and duration of diabetes. Interim stroke had a substantial negative impact on fatigue and physical function. Darbepoetin alfa confers a consistent, but small, improvement in fatigue and overall quality of life but not in other domains. These modest QOL benefits must be considered in the context of neutral overall effect and increased risk of stroke in a small proportion of patients. Patient's QOL and potential treatment risk should be considered in any treatment decision.