Objective: Although the prevalence of adult ADHD has been well established in the general population, few studies have examined the prevalence of ADHD symptoms in the military. Method: The present study used data from 21,449 active duty soldiers, whose responses were collected as part of the Army Study to Assess Risk and Resilience in Servicemembers (Army STARRS). Positive ADHD screens were identified using two alternative scoring methods of the Adult Self-Report ADHD Scale Screener. Results: The estimated prevalence of ADHD in this sample was 7.6% and 9.0% depending on diagnostic method. Contrary to initial hypotheses that ADHD would be highest in the 18- to 19-year-old age-group, the age distribution of ADHD in this study was centered around the 25- to 29-year-old age-group. Conclusions: The findings of this study indicate that adult ADHD symptoms are common in Army personnel, and are not limited to the youngest cohorts. Implications on screening, administrative policy, and future research directions are also discussed.