Background There have been few evaluations of national area-based interventions. This study evaluated the early effects of Commmunities for Children (CfC) on children and their families and whether the effectiveness differed for more disadvantaged families.

Methods A quasi-experimental cohort study in socioeconomically disadvantaged communities in Australia. Mothers of children aged 2–3 years participated at wave 1; 1488 children in CfC communities and 714 children in comparison communities. Outcome measures included child health and development, family functioning and parenting, and services and community.

Results After controlling for background factors, there were beneficial effects associated with CfC. At wave 3, in CfC areas children had higher receptive vocabulary (mean difference (MD) 0.25, 95% CI −0.02 to 0.51; p=0.07), parents showed less harsh parenting (MD −0.14, 95% CI −0.30 to 0.02; p=0.08) and higher parenting self-efficacy (MD 0.11, 95% CI 0.00 to 0.21; p=0.04). Fewer children living in CfC sites were living in a jobless household (OR 0.56, 95% CI 0.32 to 0.95; p=0.03) but children's physical functioning (MD −0.26, 95% CI −0.53 to 0.00; p=0.05) was worse in CfC sites. For children living in households with mothers with low education there were reduced child injuries requiring medical treatment (MD −0.61, 95% CI −0.07 to −1.13; p=0.03) and increased receptive vocabulary (MD 0.57, 95% CI 0.06 to 1.08; p=0.03).

Conclusions CfC showed some benefits for child receptive vocabulary, parenting and reducing jobless households and two adverse effects. Children living in the most disadvantaged households also benefited.