It is estimated that 2.1 million people in the United States abuse prescription opioid pain medications. Hydrocodone-containing products are the most frequently prescribed opioids in U.S. emergency departments (ED). In 2012, the Centers for Disease Control and Prevention linked the rise in prescription opioid use to an increase in drug overdoses and opioid abuse. We sought to measure national prescribing patterns for hydrocodone/acetaminophen (HD/A) among veterans seeking emergency medical care, and to see if patterns have changed since this medication was reclassified by the Drug Enforcement Agency in 2014. We conducted a retrospective cohort study of ED visits within the Veterans Health Administration (VA) between January 2009 and June 2015. We looked at age, sex and ethnicity demographics, comorbidities, utilization measures, diagnoses, and prescriptions. Data was obtained from the VA Informatics and Computing Infrastructure (VINCI). In addition, for each visit, characteristics were organized by year to identify trends in prescribing habits. Patients were excluded if age, sex, or diagnosis was missing from their chart. Descriptive statistics were used. The chi-square test, with 95% intervals, was used to examine differences between characteristics among groups. Pearson’s correlation coefficient was used to evaluate prescribing trends per year. Multivariate logistic regression was used to determine the characteristics that best predicted who received a prescription for HD/A. Approval was granted by the institutional IRB. During the study period, 1,709,545 individuals participated in 6,270,742 ED visits and received 471,221 prescriptions for HD/A. The most common diagnosis associated with a prescription was back pain (16.2% of all HD/A scripts). Prescriptions peaked at 80,776 in 2011 (8.7% of visits), and declined to 35,031 (5.6%) during the first half of 2015 (r =‒0.99, p <0.001). The percentage of HD/A ED prescriptions limited to 12 pills increased from 22% (13,949) in 2009 to 31% (11,026) in the first half of 2015. A prescription was more likely for patients with a pain score ≥7 (OR 3.199, CI 3.192‒3.205), a musculoskeletal (OR 1.622, CI 1.615‒1.630) or soft tissue (OR 1.656, CI 1.649‒1.664) diagnosis, those with 3 ED visits or less during their tenure with the VA system (1st quartile, OR 1.282, CI 1.271‒1.293), males (OR 1.112, CI 1.100-1.123) and Caucasians (OR 1.213, CI 1.201-1.220). Patients less likely to be given HD/A prescriptions were those with a Comorbidity-Polypharmacy score below 14 (first quartile, OR 0.836, CI 0.826-0.847) those with a dual mental health/substance abuse diagnosis (OR 0.972, CI 0.959-0.985) and those patients older than 66 years of age (third quartile for age, OR 0.679, CI 0.670-0.688). Hydrocodone/acetaminophen is the most frequently prescribed ED medication in the VA. Demographics, comorbidities, and specific diagnoses influence HD/A prescription dispensation in the ED. Overall, the rate of prescribing has decreased since 2011, with the rate of decline starting before it was reclassified as a Schedule II controlled substance. The proportion of ED prescriptions for HD/A meeting best practice guidelines has increased, but is not at goal.