OBJECTIVES: The use of azacitidine has been recently approved in Spain for the treatment of adult patients (pts) ≥65 years diagnosed with Acute Myeloid Leukemia (AML) with >30% marrow blasts who are ineligible for hematopoietic stem cell transplantation (HSCT). The objective was to assess the economic impact of treating these pts with azacitidine in Spain. METHODS:  From the National Health System (NHS) perspective, we developed a budget impact analysis to assess azacitidine eligibility and costs over a 3-year period. The number of pts aged ≥65 years with AML and >30% marrow blasts was estimated using published epidemiologic estimates. The proportion of those pts ineligible for HSCT was obtained through local expert consultation. AML market distribution was obtained from market research studies. For all therapeutic options, healthcare costs (€2016) included drug (ex-factory considering compulsory RDL 8/2010 discount), administration and adverse events. Unit costs were obtained from the NHS and eSalud databases. The base-case analysis considered that vial-sharing was performed for all treatment alternatives. RESULTS: