Preschool children living in low-income families are at increased risk for poor outcomes; early intervention programmes mitigate these risks. While there is considerable evidence of the effectiveness of centre-based programmes in other jurisdictions, there is limited research about Canadian programmes, specifically programmes that include children and parents. The purpose of this study was to evaluate a single-site, two-generation preschool demonstration programme for low-income families in Canada. A single group, pre-test (programme intake) /post-test (programme exit) design with a 7-year-old follow-up was used. Between intake and exit, significant improvements in receptive language and global development were found among the children, and significant improvements in self-esteem, use of community resources, parenting stress and risk for child maltreatment were found among the parents. These positive improvements were sustained until the children were 7 years old. Public investment in two-generation preschool programmes may mitigate risks for suboptimal child development and improve parental psychosocial outcomes.