Addison's disease or primary adrenal insufficiency is a rare disease in children. The signs and symptoms at diagnosis are frequently non-specific and insidious. Since adrenal crisis represents an emergency, it is important to be aware and to have a high degree of suspicion of the disorder in order to achieve an early diagnosis and treatment. We present a retrospective study describing the epidemiological, clinical and etiological data at diagnosis of five patients with Addison's disease followed up in our hospital. Dehydration, hyponatremia and skin hyperpigmentation were the most prevalent signs and symptoms at onset of the disease. The patients had low serum cortisol levels and positive adrenal antibodies. One patient with negative antibodies presented with a polyglandular syndrome.