Introduction: Most studies evaluating prescription opioid dependence or misuse are retrospective and are based on prescription filling rates from pharmaceutical databases. These studies cannot evaluate if opioids are really consumed nor differentiate if used for a new pain, chronic pain, or for misuse/dependence. The aim of this study was to assess the opioid consumption in emergency department (ED) patients three months after discharge with an opioid prescription. Methods: This prospective cohort study was conducted in the ED of a tertiary care centre with a convenience sample of patients aged 18 years and older, recruited 24/7, who consulted and were discharged for an acute pain condition ( 2 weeks). We excluded patients who: did not speak French or English, were using opioid medication prior to their ED visit, with an ED stay > 48 hours, or suffering from cancer or chronic pain. Three months post-ED visit, participants were contacted by phone for a structured interview on their past two-week opioid use, their reasons for consuming them, and also answered the Rapid Opioid Dependence Screen (RODS) questionnaire. Results: In the 524 participants interviewed at three months (mean age ± SD: 51±16 years, 47% women), 44 (8.4%) patients consumed opioids in the previous two weeks. Among those, 72% consumed opioids for their initial pain, 19% for a new unrelated pain, and 9% for another reason. In this entire cohort, only five patients (1%) tested positive to opioid dependence from the RODS test. The low dependence incidence could be affected by a social desirability bias. Conclusion: This study suggests that opioid use at 3-month, for patients initially treated for acute pain, is associated with opioid dependency in 1% or possible misuse in only 9%. Additional prospective studies using multiple methods to measure opioids consumption, misuse, and dependence are needed.