A specific cause of anemia cannot be identified in many elderly patients. Erythropoiesis-stimulating agents (ESAs) may play a role in treating these patients with anemia of unknown etiology (AUE). This study examines hemoglobin and cardiovascular outcomes among elderly anemic patients treated with ESAs. We conducted a retrospective cohort study that included all anemic patients older than age 60 years who had erythropoietin (EPO) measured between 2005 and 2013 at a single center. Three independent reviewers used defined criteria to assign each patient's anemia to 1 of 4 groups: chronic kidney disease (CKD), myelodysplastic syndrome, AUE, or other etiology. Logistic regression was used to compare treatment response (defined per the International Working Group response criteria in myelodysplasia). Adjusted Cox regression analysis was used to calculate the cardiovascular event hazard ratios associated with ESA treatment. A total of 570 patients met the inclusion criteria, of whom 101 received ESAs. There was a nonstatistically significant but quantitatively better response in AUE (47%) and CKD (54%) compared with other etiologies (22%). The adjusted odds ratio for response in AUE compared with other etiologies was 3.3 (95% confidence interval, 0.838-13.0). A baseline EPO level <200 IU/L independently predicted treatment response. There was no statistically significant difference in cardiovascular events or cardiovascular event-free survival between the treated and untreated groups after adjusting for confounders. Our results suggest that ESAs may effectively treat AUE, and responses may be similar to those in CKD. We could not detect a statistically significant increase in cardiovascular events in the studied cohort.