The opioid epidemic in the United States has resulted in over 42,000 U.S. opioid overdose fatalities in 2016 alone. In New York City (NYC) opioid overdoses have reached a record high, increasing from 13.6 overdose deaths/100,000 to 19.9/100,000 from 2015 to 2016. Supervised injection facilities (SIFs) provide a hygienic, safe environment in which pre-obtained drugs can be consumed under clinical supervision to quickly reverse opioid overdoses. While SIFs have been implemented worldwide, none have been implemented to date in the United States. This study estimates the potential impact on opioid overdose fatalities and healthcare system costs of implementing SIFs in NYC.A deterministic model was used to project the number of fatal opioid overdoses avoided by implementing SIFs in NYC. Model inputs were from 2015 to 2016 NYC provisional overdose data (N = 1852) and the literature. Healthcare utilization and costs were estimated for fatal overdoses that would have been avoided from implementing one or more SIFs.One optimally placed SIF is estimated to prevent 19-37 opioid overdose fatalities annually, representing a 6-12% decrease in opioid overdose mortality for that neighborhood; four optimally placed SIFs are estimated to prevent 68-131 opioid overdose fatalities. Opioid overdoses cost the NYC healthcare system an estimated $41 million per year for emergency medical services, emergency department visits, and hospitalizations. Implementing one SIF is estimated to save $0.8-$1.6 million, and four SIFs saves $2.9-$5.7 million in annual healthcare costs from opioid overdoses.Implementing SIFs in NYC would save lives and healthcare system costs, although their overall impact may be limited depending on the geographic characteristic of the local opioid epidemic. In cities with geographically dispersed opioid epidemics such as NYC, multiple SIFs will be required to have a sizeable impact on the total number of opioid overdose fatalities occurring each year.