The National Board of Osteopathic Medical Examiners (NBOME) administers the Comprehensive Osteopathic Medical Licensing Examination of the United States (COMLEX-USA), a three-level examination designed for licensure for the practice of osteopathic medicine. The examination design for COMLEX-USA Level 3 (L3) was changed in September 2018 to a two-day computer-based examination with two components: a multiple-choice question (MCQ) component with single best answer and a clinical decision-making (CDM) case component with extended multiple-choice (EMC) and short answer (SA) questions. Continued validation of the L3 examination, especially with the new design, is essential for the appropriate interpretation and use of the test scores. The purpose of this study is to gather evidence to support the validity of the L3 examination scores under the new design utilizing sources of evidence based on Kane's validity framework. Kane's validity framework contains four components of evidence to support the validity argument: Scoring, Generalization, Extrapolation, and Implication/Decision. In this study, we gathered data from various sources and conducted analyses to provide evidence that the L3 examination is validly measuring what it is supposed to measure. These include reviewing content coverage of the L3 examination, documenting scoring and reporting processes, estimating the reliability and decision accuracy/consistency of the scores, quantifying associations between the scores from the MCQ and CDM components and between scores from different competency domains of the L3 examination, exploring the relationships between L3 scores and scores from a performance-based assessment that measures related constructs, performing subgroup comparisons, and describing and justifying the criterion-referenced standard setting process. The analysis data contains first-attempt test scores for 8,366 candidates who took the L3 examination between September 2018 and December 2019. The performance-based assessment utilized as a criterion measure in this study is COMLEX-USA Level 2 Performance Evaluation (L2-PE). All assessment forms were built through the automated test assembly (ATA) procedure to maximize parallelism in terms of content coverage and statistical properties across the forms. Scoring and reporting follows industry-standard quality-control procedures. The inter-rater reliability of SA rating, decision accuracy, and decision consistency for pass/fail classifications are all very high. There is a statistically significant positive association between the MCQ and the CDM components of the L3 examination. The patterns of associations, both within the L3 subscores and with L2-PE domain scores, fit with what is being measured. The subgroup comparisons by gender, race, and first language showed expected small differences in mean scores between the subgroups within each category and yielded findings that are consistent with those described in the literature. The L3 pass/fail standard was established through implementation of a defensible criterion-referenced procedure. This study provides some additional validity evidence for the L3 examination based on Kane's validity framework. The validity of any measurement must be established through ongoing evaluation of the related evidence. The NBOME will continue to collect evidence to support validity arguments for the COMLEX-USA examination series.