ObjectiveTo describe the national delivery of medication therapy management (MTM) to Medicare beneficiaries in 2013 and 2014. MethodsDescriptive cross-sectional study using the 100% sample of 2013 and 2014 Part D MTM data files. We quantified descriptive statistics (counts and percentages, in addition to means and standard deviations) to summarize the delivery of these services and compare delivery between 2013 and 2014. ResultsMedicare beneficiaries eligible for MTM increased from 4,281,733 in 2013 to 4,552,547 in 2014. Among eligible beneficiaries, the number and percentage who were offered a comprehensive medication review (CMR) increased from 3,473,004 (81.1%) to 4,394,822 (96.5%), and beneficiaries receiving a CMR increased from 526,203 (12.3%) to 767,286 (16.9%). In 2014, CMRs were most frequently delivered by telephone (83.2%) and provided by either a plan sponsor (29.0%) or an MTM vendor in-house pharmacist (35.0%). In 2014, pharmacists provided 93.5% of all CMRs, and other providers (e.g., nurses and physicians) provided 6.5% of CMRs. Few patients who received a CMR received more than 1 within the same year (2.2% in 2014). Medication therapy problem (MTP) resolution among patients receiving a CMR stayed roughly the same between 2013 and 2014 (19.2% vs. 18.7%, respectively; P < 0.001). Finally, most beneficiaries (96.9% in 2014) received a targeted medication review, regardless of whether a CMR was offered or provided. ConclusionMore than 4 million Medicare beneficiaries were enrolled in Part D MTM in both 2013 and 2014. However, less than 20% of eligible beneficiaries received a CMR during those years, and rates of MTP resolution were low. Future evaluation of Part D MTM delivery should examine changes in eligibility criteria and delivery over time to inform MTM policy and changes in practice.