This paper reports on the design, methodology, and results of a study of quality in 326 classrooms in 239 Canadian child care centers. This study, the largest and most extensive ever undertaken in Canada, used the Caregiver Interaction Scale (CIS) to rate the adult-child interactions in the classrooms and the Infant-Toddler Environment Rating Scale (ITERS) and the Early Childhood Environment Rating Scale-Revised (ECERS-R) to measure the quality of classroom learning environments. The observed staff members completed questionnaires on wages, working conditions, and satisfaction levels, and the center directors also completed questionnaires on center operations and finances. Path analyses revealed that in the infant/toddler rooms the number of adults in the observed classroom and the education level of the observed staff member were direct predictors of quality. In addition, there were three indirect predictors: parent fees, adult:child ratio, and use of the center as a student teacher practicum site. There were five significant direct predictors in the preschool classrooms: wages, education level, number of staff in the observed room, staff satisfaction, and whether the center received free or subsidized rent or utilities. The three indirect predictors were auspice, adult:child ratio, and parent fees. The interaction of distal and proximal factors is interpreted and applied to the development and implementation of public policy initiatives that can provide much-needed improvement to the overall mediocre levels of child care quality in Canada.