Baseline data from the Canadian National Longitudinal Survey of Children and Youth were used to evaluate the associations between child care arrangement and poor developmental attainment (PDA). A weighted total of 521,800 children aged 2 to 3 years were studied (N = 2,709). PDA was assessed by age-standardized motor and social development score. Children were grouped by the predominant type of arrangement: care by someone in the child's own home, in another home (family child care), at a child care centre, or none (child care exclusive to parents). Controlling for socioeconomic status, biological factors and maternal immigration, family dysfunction, hostile parenting and low neighbourhood safety were correlated with PDA and positive parent-child interaction decreased the odds of PDA. Whereas centre child care arrangements were beneficial to development overall (OR = 0.41, 99% CI = 0.18, 0.93), an interaction existed between type of child care and maternal depression; among children with depressed mothers, centre child care was associated with increased odds of PDA. Findings suggest that the associations between child care arrangement and child development involve interactions of factors that influence a child's home environment. Future child development studies exploring these interactions are warranted.