Food and Drug Administration (FDA) and Centers for Medicare and Medicaid Services (CMS) rely on evidence from clinical trials when approving a therapeutic for marketing and insurance coverage in the US, respectively. No study has compared the quality and quantity of evidence examined by these agencies.To characterize evidence used by FDA and CMS to support marketing approval and National Coverage Determinations (NCDs), respectively, of novel therapeutics reviewed for CMS coverage from 2005 through 2016.A cross-sectional study of clinical trials described in FDA approval documents and CMS NCD memoranda. We compared the number of clinical trials used by each agency as well as the following characteristics among original clinical trials: study size, randomization, double-blinding, and control arm.Twelve medical products met our inclusion criteria. FDA approvals of these products were based on 22 pivotal trials. CMS NCDs were based on 27 original clinical trials; 14 clinical trials were used by both agencies. Between FDA pivotal and CMS original clinical trials, there was no significant difference in study size (P = .53), use of randomization (P = .75), double-blinding (P = .55), or control arm (P = .54). There was no statistically significant difference in median age between participants in trials reviewed by CMS versus those reviewed by FDA (62 vs 59 years, P = .26). The median time from FDA approval to publication of CMS NCD memorandum was 17 (interquartile range, 13-36) months.FDA approvals and CMS NCDs are based on a similar number and quality of trials, although trial participants are not reflective of the Medicare population, and the process of finalizing coverage determinations requires an additional 17 months.