Importance: Previous studies that examined the role of household opioid prescriptions in opioid overdose risk were limited to commercial claims, did not include fatal overdoses, and had limited inclusion of household prescription characteristics. Broader research is needed to expand understanding of the risk of overdose.

Question: What role do household opioid prescription availability and prescription characteristics play in an individual’s odds of opioid overdose?

Findings: In this cohort study of 1 691 856 Oregon adults in 1 187 140 households, the odds of opioid-related overdose increased significantly when another household member had opioid fills in the preceding 6 months. The odds also increased when both the individual and another household member had opioid fills in the preceding 6 months.

Meaning: The findings of this cohort study underscore the importance of educating individuals about the risks of keeping opioids in the household.