PurposeThe National Board of Medical Examiners® (NBME) Comprehensive Basic Science Exam (CBSE) is a subject exam offered to US medical schools, where it has been used for external validation of student preparedness for the United States Medical Licensing Examination® (USMLE) Step 1 in new schools and schools undergoing curricular reform. Information regarding the actual use of the NBME CBSE is limited. Therefore, the aim of the survey was to determine the scope and utilization of the NBME CBSE by US medical schools.MethodsA survey was sent in May 2016 to curriculum leadership of the 139 US medical schools listed on the Liaison Committee on Medical Education (LCME®) website with provisional or full accreditation as of February 29, 2016. Responses were received from 53 schools (38% response rate). A series of different follow-up questions were asked if respondents stated “yes” or “no” to the initial question “Does your institution administer the NBME CBSE prior to the USMLE Step 1?”.ResultsA total of 37 schools (70%) administered the NBME CBSE. In all, 36 of the 37 schools responded to follow-up questions. Of 36 schools, 13 schools (36%) used the NBME CBSE for curriculum modification. Six schools (17%) used the NBME CBSE for formative assessment for a course, and five schools (14%) used the NBME CBSE for summative assessment for a course. A total of 28 schools (78%) used the NBME CBSE for identifying students performing below expectations and providing targeted intervention strategies. In all, 24 schools (67%) of the 36 responding schools administering the NBME CBSE administered the test once prior to the administration of the USMLE Step 1, whereas 10 (28%) schools administered the NBME CBSE two or more times prior to the administration of the USMLE Step 1.ConclusionOur data suggest that the NBME CBSE is administered by many US medical schools. However, the objective, timing, and number of exams administered vary greatly among schools.