Partnerships between Early Head Start (EHS) programs and child care providers strive to improve access to high-quality, comprehensive services for infants and toddlers whose families have low incomes. Early Head Start-Child Care (EHS-CC) Partnership grants provide a dedicated funding stream to support some of these partnerships. In 2015, the Administration for Children and Families awarded 250 such grants to support partnerships between EHS programs and regulated child care providers, including centers and family child care (FCC) providers. This report offers insights into the factors affecting the sustainability of these partnerships between 2016 and 2022. We draw on two data sources. The National Descriptive Study (NDS) of EHS-CC Partnerships of 2016--the first national study of EHS-CC Partnerships--contained information on the EHS programs and providers funded through the 2015 round of grants. The EHS-CC Partnership Sustainability Study of 2022 followed up with the EHS programs and providers in the NDS to find out whether their Partnerships lasted and what factors supported or impeded their sustainability. Research questions include: (1) What were the features of EHS programs that partnered with child care providers in 2016 and in 2022?; (2) Were the Partnerships between EHS programs and child care providers in place in 2016 still in place in 2022?; (3) What COVID-19 pandemic-related supports did providers in sustained Partnerships receive, and how did the pandemic affect their child care businesses and Partnerships with EHS programs?; (4) What factors did EHS programs and child care providers perceive to have facilitated or prevented sustainability?; and (5) What features of EHS programs and child care providers in 2016 predicted sustained Partnerships in 2022?