The secretary of the US Department of Health and Human Services in February 2016 recommended that X-linked adrenoleukodystrophy (X-ALD) be added to the recommended uniform screening panel for state newborn screening programs. This decision was informed by data presented on the accuracy of screening from New York, the only state that currently offers X-ALD newborn screening, and published and unpublished data showing health benefits of earlier treatment (hematopoietic stem cell transplantation and adrenal hormone replacement therapy) for the childhood cerebral form of X-ALD. X-ALD newborn screening also identifies individuals with later-onset disease, but poor genotype-phenotype correlation makes predicting health outcomes difficult and might increase the risk of unnecessary treatment. Few data are available regarding the harms of screening and presymptomatic identification. Significant challenges exist for implementing comprehensive X-ALD newborn screening, including incorporation of the test, coordinating follow-up diagnostic and treatment care, and coordination of extended family testing after case identification.Genet Med 19 1, 121-126.