INTRODUCTION: In the prehospital setting opioid overdose is often treated with naloxone. In our physician-based medical emergency care unit (MECU) we have adopted a discharge-on-scene policy, where patients are released on scene if no residual signs of opioid intoxication are found after treatment. The aim of this study was to describe our experience with the discharge-on-scene policy used during a 10-year-period with focus on the frequency of rebound opioid toxicity. METHODS: Data were prospectively recorded in our MECU database and we reviewed all cases of opioid overdose between 1994 and 2003. The MECU database was cross-referenced with the Central Personal Registry. For patients who died within 48 h of MECU contact we reviewed the forensic autopsy reports to establish whether rebound opioid toxicity was likely. RESULTS: We found 4762 cases of acute opioid overdose. In 3245 cases positive identification was obtained. Over this ten year period fourteen patients who were released on-scene after having been treated with naloxone died within 48 h, but only in 3 of these we found a rebound opioid toxicity to be the likely cause of death, corresponding to 0.13% of those 2241 released on scene who were identified. CONCLUSION: Prehospital discharge-on-scene after naloxone treatment is associated with a low risk of death due to rebound toxicity