Research examining the effects of subsidized childcare prior to school entry for child development is inconsistent. This population-based study examines the relationship between two poverty levels (extreme poor and working poor) and children's developmental outcomes, as measured by the Early Development Instrument. It also determines the extent to which receipt of subsidized childcare prior to school entry provides a protective factor against the extreme poverty effects on children's developmental outcomes and whether this buffering effect is more pronounced for children with special needs. Results demonstrate that children experiencing extreme poverty, regardless of special needs status, are more likely to show readiness deficits before school onset than children from working-poor families; however, prior enrollment in subsidized childcare can offset some readiness concerns in extremely poor families, particularly for the child's language, literacy, and communication skills. Additionally, the benefits of subsidized childcare experience prior to school entry were found to be more pronounced for children with special needs than those without. This study presents one of the few Canadian perspectives on subsidized childcare using the unique Manitoba Center for Health Policy Data Repository that links data from different provincial databases, including health care, education, family services, and justice.