Importance: Studies have suggested a rise in opioid- and stimulant-involved overdoses in recent years in North America. This risk may be acute for individuals who have had contact with the criminal justice system, who are particularly vulnerable to overdose risk.

Question: What is the association between opioid and/or stimulant use disorder diagnoses and fatal and nonfatal overdose among people with a history of incarceration?

Findings: In this cohort study of 6816 individuals with a history of incarceration, people with both opioid and stimulant use disorder diagnoses had approximately 2.5 times the hazard of overdose compared with people with no substance use disorder diagnoses. Stimulant use disorder alone was associated with a similar hazard of fatal overdose as opioid use disorder alone.

Meaning: These findings suggest that in the context of an ongoing overdose public health emergency that disproportionally impacts people with histories of incarceration, there is an urgent need for attention to the service needs of individuals who have had contact with the criminal justice system who co-use opioids and stimulants.