Introduction: Emergency Department (ED) opioid prescribing has been linked to long-term use and dependence. Small packets of opioid medications are sometimes prescribed at discharge, i.e. ‘To-Go’, in an attempt to treat pain but avoid unintended consequences. The extent of this practice and its associated risks are not fully understood. This study's objective was to describe the use of ‘To-Go’ opioids in a large urban center. Methods: Multicenter linked administrative databases were used to recruit an observational cohort. The referral population was comprised of all patients discharged from a Calgary ED in 2016 (four hospitals) with an arrival pain score greater than 0. We first described this population and then performed a multivariable analysis to assess for predictors of ‘To-Go’ opioids. ‘To-Go’ opioids were either Tylenol-Codeine or Tylenol-Oxycodone. Results: A total of 88,855 patients were recruited. The majority were female (57%) and the average age was 44.5 yrs. Abdominal pain was the most frequent complaint (22.1%) followed by extremity (18.3%) and cardiac pain (8.0%). Overall, 2,736 patients (3.1%) received an opioid ‘To-Go’ with significant variation in prescribing rates across hospitals (1.8-5% Chi2 p < 0.05). Logistic regression (covariates: age, sex, CTAS, pain score, type of pain, hospital, ED opioid, length of stay) revealed that receiving an opioid (IV or PO) prior to discharge was the strongest predictor of ‘To-Go’ opioid (OR 6.4 [5.9-7.0]). Hospital (OR 1.4 [1.3-1.4]) and male sex (OR 1.2 [1.1-1.3]) also emerged as predictors, whereas age over 65 decreased the odds of ‘To-Go’ opioid (OR 0.8 [0.6-0.9]). Hospital-specific ORs ranged from 1.3-2.7. Conclusion: In comparable patient populations some hospitals are more likely than others to provide a short course of opioids at discharge. This difference is not explained by patient demographics, pain profiles, or medications prior to discharge. The reasons for this variation are unclear but it underscores the need to determine the risks of ED opioid exposures and develop clear evidence-based prescribing guidelines.