Background: Opioid overdoses have killed almost 20,000 Canadians since 2016. To address this, Canada has established supervised consumption sites where people can use drugs in the presence of trained staff and get access to pharmacological treatments such as methadone. However, there is very little research on whether supervised consumption clients use methadone, or whether their use of methadone prevents opioid overdose. Methods: A secondary data analysis of information collected from one supervised consumption site was undertaken in order to explore relationships between client self-reported methadone dosage and subsequent observed same-day opioid overdose. Results: Statistical analysis showed no correlation between methadone usage and reduced chance of opioid overdose. However, the most common dosage of methadone reported (30mg/day) was far below the minimum therapeutic dose of methadone. Conclusion: Clients of supervised consumption sites often report being prescribed methadone, but not at a dose high enough to reduce opioid overdose.