The costs of care among privately insured children with bipolar disorder are similar to that of adults. However, spending on children is concentrated on mental health related services. This is important as private insurance plans have historically limited mental health service benefits, which may place a greater burden on families for out of pocket payments. As mental health parity is adopted by private insurers it will be important to monitor the impact on patient utilization and costs of health services, particularly for children with severe mental illness.