Inequalities in child health between tamariki Māori and non-Māori are largely preventable and unnecessary. An example is rheumatic fever, where tamariki Māori are 30 times more likely to contract the disease than non-Māori. Being ill as a child has a big impact on school attendance and outcomes, and it may cause lifelong disability or illness. There are high costs involved, for the health system, society and to whānau. This study aimed to estimate how much not doing anything to reduce child health inequities really costs us.