Through the stimulus of war and concerns about neuropsychiatric disability, the U.S. military developed methods to rapidly screen the mental health of World War I and II draftees. Intelligence testing and brief psychiatric screening expanded the accession physical examination and underwent revision to identify only gross mental health disability. Supplemental psychiatric evaluations and written psychological screening tools were abandoned after postwar assessments; they demonstrated poor predictive power in evaluating recruit service capacity for combat environments. Currently, only three mental health accession tools are used to screen applicants before their entrance into military service, namely, educational achievement, cognitive testing, and a cursory psychiatric evaluation. The Navy and Air Force use a fourth screening measure during entry-level training. Educational attainment with high school graduation has been the strongest predictor of finishing a service term. The purpose of this article is to provide both a historical review and a review of testing efforts.