More than 40% of all reported coronavirus disease 2019 (COVID-19) deaths in the United States have occurred in nursing homes. As a result, health care worker access to personal protective equipment (PPE) and infection control policies in nursing homes have received increased attention. However, it is not known if the presence of health care worker unions in nursing homes is associated with COVID-19 mortality rates. Therefore, we used cross-sectional regression analysis to examine the association between the presence of health care worker unions and COVID-19 mortality rates in 355 nursing homes in New York State. Health care worker unions were associated with a 1.29 percentage point mortality reduction, which represents a 30% relative decrease in the COVID-19 mortality rate compared to facilities without health care worker unions. Unions were also associated with greater access to PPE, one mechanism that may link unions to lower COVID-19 mortality rates.