OBJECTIVES: Erythropoiesis stimulating agents (ESAs) are be used treat anemia in cancer patients. No study, to date, has explored the economic burden of ESAs in the Medicare Part D population with cancer. Our project aims to fill this literature gap by examining health care costs associated with ESA use among Medicare beneficiaries with cancer post Medicare Part D. METHODS: This study used the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database. We used a retrospective incident user cohort design in SEER-Medicare between 2008 and 2010. Cancer patients with anemia who were enrolled in Medicare Part D were included. Patients with disabilities, end state renal disease (ESRD) and facility dwelling were excluded. A generalized linear model with a log link and gamma distribution was implemented to estimate the economic burden associated with ESAs. RESULTS: A total of 4,490 cancer patients who used ESAs were identified during the study period. The average total direct medical cost for ESA users was $55,850.92 (SD=$40,494.11) compared to $55,219.84 for ESA non-users (SD=$58,325.85). Anemia-related costs among ESA users were $7,843.67 (SD=12,544.48) compared to $9,282.03 for ESA non-users, (SD=$14,599.46). CONCLUSIONS: ESAs use is associated with slightly higher costs for the Medicare Part D program compared to the costs for non-users. However, ESA use was associated with lower total anemia-related costs suggesting an economic benefit for Part D Medicare ESA users.