Background. The United States military relies on visual acuity standards to assess enlistment induction and military occupational specialty eligibility. In addition, the military recently instituted the Vision Readiness and Classification System to monitor Soldiers' combat vision readiness. The primary aim of this study was to investigate the relationship between visual acuity and marksmanship performance using a single blind randomized trial with the Engagement Skills Trainer 2000. Methods. Marksmanship performance was evaluated in 28 subjects under simulated day and night conditions with habitual spectacle prescription and contact lenses that created visual blur. Results. The relationship between visual acuity and marksmanship performance was found to have a statistically significant correlation of -0.735 with a 95% confidence interval from -0.790 to -0.669. Subsequently, 54 percent of the variance in marksmanship performance was accounted for by visual acuity. In addition, a panel poison regression model using an independent correlation structure revealed significant differences (p< .001) as visual acuity decreased from 20/25 to 20/50. Conclusions. Marksmanship performance decreases as visual acuity decreases. This relationship supports the use of a visual acuity requirement in the assessment of military readiness.