The glucocorticoid-induced inhibition that occurs after discontinuation of treatment is the most frequent cause of adrenal insufficiency. There are yet some doubts about the best way of evaluating the hypothalamic-pituitary-adrenal (HPA) axis in those patients. The main objective of this study was to evaluate the utility of basal cortisol in diagnosing adrenal insufficiency. Thirty-five children with acute lymphoid leukemia (ALL) receiving glucocorticoid therapy (median age of 6.9 years) were evaluated. A stimulus test with corticotropin releasing hormone (CRH