INTRODUCTION: Children born into families at risk of becoming or remaining poor are at significant risk of experiencing childhood poverty, which can impair their start to life, and perpetuate intergenerational cycles of poverty. This study sought to quantify health service utilisation, costs and funding distribution amongst children born into vulnerable compared to non-vulnerable families. METHODS: This study used a large linked administrative dataset for all women giving birth in Queensland, Australia between July 2012 and July 2018. Health service use included inpatient, emergency department (ED), general practice, specialist, pathology and diagnostic imaging services. Costs included those paid by public hospital funders, private health insurers, Medicare and out-of-pocket costs. RESULTS: Vulnerable children comprised 34.1% of the study cohort. Compared with non-vulnerable children, they used significantly higher average numbers of ED services during the first 5 years of life (2.52±3.63 vs 1.97±2.77), and significantly lower average numbers of specialist, pathology and diagnostic imaging services. Vulnerable children incurred significantly greater costs to public hospital funders compared with non-vulnerable children over the first 5 years of life ($16 053 vs $10 247), and significantly lower private health insurer, Medicare and out-of-pocket costs. CONCLUSION: There are clear inequities in vulnerable children's health service utilisation in Australia. Greater examination of the uptake and cost-effectiveness of maternal and child services is needed, as these services support children's development in the critical first 1000 days of life.