This study examines the effects of child care arrangements on children's cognitive outcomes. It is a secondary analysis, using data on 5107 children born in 2004 and their families from Growing Up in Australia: The Longitudinal Study of Australian Children. Data were collected in 2004 (Wave One), in 2006 (Wave Two) and in 2008 (Wave Three). This study asks (i) Do children receiving non-parental child care have different cognitive developmental outcomes at ages 4-5, compared with those who never had non-parental child care during the first 3 years of life? Do parental factors affect these associations?; and (ii) among children with non-parental child care, do child care characteristics such as types of care, quantity, entry age and stability of child care affect child outcomes? Do parental factors affect child outcomes? The study's findings suggest that children in non-parental child care had higher Peabody Picture Vocabulary Test scores at age 5. Among children in non-parental child care arrangements, quantity and entry age of non-parental child care affected children's cognitive developmental outcomes. Along with child care arrangements, parental mental health was associated with children's cognitive outcomes. (author abstract)