OBJECTIVES: The objectives of this study were to estimate the prevalence of opioid overdoses in prescription opioid users, their family members and in overdose victims with no identifiable source of prescription opioid (“others”), and to estimate incremental costs and resource utilization associated with opioid overdoses in these groups. METHODS: This study was a retrospective analysis using claims data from SelectHealth, a not-for-profit health insurance organization serving members in Utah and southern Idaho. The data were from June 2010 through July 2015. We estimated the prevalence of opioid overdoses by year for each group. For cost estimation, family members and others were collapsed into a “non-medical users” category. We used an incremental cost approach whereby cases (patients who suffered from an opioid overdose) were propensity-score matched to controls (did not suffer from an opioid overdose) and estimated the direct medical costs and resource utilization incurred in each group in the year following an overdose. Generalized Linear Models were used to estimate incremental costs and resource utilization. RESULTS: The prevalence of overdoses increased by 84.8% in prescription opioid users (102.8 per 100,000 in 2014), by 37.9% in their family members (8.2 per 100,000 in 2014) and by 179.9% in others group from 2011 to 2014 (23.1 per 100,000 in 2014). Incremental direct medical costs associated with opioid overdose were estimated to be $65,277 per patient per year in prescription opioid users and $41,102 (p-values<0.05) in non-medical users. Overdose-specific costs were estimated to be $12,111 for prescription opioid users and $11,070 for non-users. Resource utilization was significantly higher among those who experienced an overdose across all places of service. CONCLUSIONS: The prevalence of opioid overdoses increased steadily from 2011 to 2014. Differences between overdose-specific costs and total incremental costs may suggest that overdoses are associated with substantial downstream costs.