Primary adrenal insufficiency is a rare pediatric condition, which can be presented as chronic or acute forms, especially during stress. The clinical features are unspecific and include weakness, nausea and vomiting, abdominal pain and diarrhea, arterial hypotension, hypoglycemia and dehydration. The etiology can be acquired such as infectious, hemorrhagic and drug-induced disorders, or be dependent on a genetic origin, such as congenital adrenal hyperplasia, Addisons disease, congenital adrenal hypoplasia, adrenoleucodystrophy, or deposit disorders of the adrenal gland. The familial history, presence of consanguinity, adjacent diseases and associate factors, should be considered to confirm the diagnosis. Laboratory investigation includes cortisol, ACTH and the determination of the steroidogenic precursors. The ACTH stimulation test is performed in intermediate conditions. Adrenal auto-antibodies quantitation and molecular studies can be helpful to confirm specific diseases. A substitutive glucocorticoid and mineralocorticoid therapy should be started as soon as the diagnosis is confirmed. The treatment aimed to control the symptoms with the smaller dose that can allow an adequate growth and pubertal development.