The current article will review the newest diagnostic tools, genetic causes, and treatment of adrenal insufficiency in children.It is common practice to perform an adrenocorticotropin hormone (ACTH) stimulation test when adrenal insufficiency is suspected. The indications for use of a high-dose or low-dose of synthetic ACTH in children have been refined. In addition, newer studies propose adding 15 and 30-min serum or salivary cortisol levels to the low-dose ACTH stimulation test to correctly identify adrenal insufficiency. Recent identification of genetic mutations in children with non-classic steroidogenic acute regulatory protein and other mutations associated with primary and secondary adrenal insufficiency have expanded the cause and pathophysiology of monogenic adrenal insufficiency. In addition, newer hydrocortisone formulations and delivery methods and medications to use in combination with hydrocortisone are being explored to improve treatment for children with adrenal insufficiency.Improved diagnostic aids, detection of newer genetic mutations, and better treatment options and delivery systems will help correctly identify and manage children with adrenal insufficiency to improve health outcomes and quality of life.http://links.lww.com/COE/A21.