Recent studies show that children who die from fulminant meningococcaemia have very low cortisol:adrenocorticotrophic hormone (ACTH) ratios within the first 8 h of presentation to emergency facilities compared with survivors. This observation supports the possibility that adrenal insufficiency may contribute to rapid cardiovascular collapse in these children. In recent years, the use of hydrocortisone treatment has become increasingly popular in the care of adult and paediatric patients with septic shock. In this review, the classical adrenal insufficiency literature is presented and the existing rationale for using titrated hydrocortisone treatment (2-50 mg/kg/day) to reverse catecholamine-resistant shock in children who have absolute adrenal insufficiency (defined by peak cortisol level <18 microg/dl after ACTH challenge) or pituitary, hypothalamic or adrenal axis insufficiency is provided. In addition, the concept of relative adrenal insufficiency (basal cortisol >18 microg/dl but a peak response to ACTH <9 microg/dl) is reviewed. Although there is a good rationale supporting the use of 7 days of low-dose hydrocortisone treatment (about 5 mg/kg/day) in adults with this condition and catecholamine resistant septic shock, the paediatric literature suggests that it is prudent to conduct more studies before recommending this approach in children.