OBJECTIVES: Veterans Health Administration (VHA) launched a national initiative to train providers in a specific, protocolized auricular acupuncture treatment (also called Battlefield Acupuncture or BFA) as a nonpharmacological approach to pain management. This evaluation assessed the real-world effectiveness of BFA on immediate pain relief and identified subgroups of patients for whom BFA is most effective. RESEARCH DESIGN: In a cross-sectional cohort study, electronic medical record data for 11,406 Veterans treated with BFA at 57 VHA medical centers between October 2016 and September 2018 was analyzed. The multivariate analysis incorporated data on pain history, change in pain level on an 11-point scale, complications, and demographic information. METHODS: A total of 11,406 Veterans were treated with BFA at 57 VHA medical centers between October 2016 and September 2018 and had effectiveness data recorded in their electronic medical record. RESULTS: More than 3 quarters experienced immediate decreases in pain following administration of BFA, with nearly 60% reported experiencing a minimal clinically important difference in pain intensity. The average decrease in pain intensity was -2.5 points (SD=2.2) at the initial BFA treatment, and -2.2 points (SD=2.0) at subsequent treatments. BFA was effective across a wide range of Veterans with many having preexisting chronic pain, or physical, or psychological comorbid conditions. Veterans with opioid use in the year before BFA experienced less improvement, with pain intensity scores improving more among Veterans who had not recently used opioids. CONCLUSION: VHA's rapid expansion of training providers to offer BFA as a nonpharmacological approach to pain management has benefited many Veterans.