Objective: Combat exposure can increase the risk of subsequent psychological ill-health in armed forces (AF) personnel. A U.S. postdeployment psycho-educational intervention, Battlemind, showed a beneficial effect on mental health in U.S. military personnel exposed to high combat levels. We evaluated the effectiveness of an anglicized version of postdeployment Battlemind. Method: Battlemind was adapted for the United Kingdom. The main amendments were to sections about carrying weapons, driving, and alcohol misuse. The anglicized Battlemind was compared with the U.K. standard postdeployment brief in a cluster randomized controlled trial. At baseline, 2,443 U.K. AF personnel returning from Afghanistan via Cyprus completed questionnaires about their combat experiences and mental health. Of these, 1,616 (66%) completed 6-month follow-up questionnaires. We used the Posttraumatic Stress Disorder Checklist (PCL-C) to measure probable posttraumatic stress disorder and the General Health Questionnaire (GHQ-12) to measure common mental disorders. Secondary outcomes included alcohol misuse, assessed with the Alcohol Use Disorders Identification Test (AUDIT), and binge drinking. Mixed-effects models were used to account for possible cluster effects. Results: We did not find a difference in mental health or overall AUDIT score. Those who received Battlemind versus the standard brief were less likely to report binge drinking, although the effect size was small (adjusted odds ratio = 0.73, 95% CI [0.58, 0.92]). Conclusions: The anglicized Battlemind did not improve mental health but had a modest impact on the reporting of binge drinking. Alcohol misuse is problematic in military populations; therefore, an intervention that reduces binge drinking may be helpful. (Contains 4 tables and 1 figure.)