The aim of the study was to assess glucocorticoid sensitivity in survivors of childhood acute lymphoblastic leukemia using in vivo and in vitro tests. Thirty leukemia survivors of both sexes aged ≥18 years participated in the study and at least two years after therapy withdrawal. In vivo tests comprised: a) a very low dose intravenous dexamethasone suppression test for measurement of serum cortisol before, after, and % suppression, compared with 32 age-matched controls; and b) 0.25 mg overnight oral dexamethasone suppression test for assessment of salivary cortisol before, after, and % suppression. In vitro methods comprised: c) glucocorticoid receptor polymorphisms: BcI1-NR3C1 and A3669G; and d) splicing variant of glucocorticoid receptor GR-α mRNA by real-time quantitative polymerase chain reaction, compared with 32 controls. There was a reduction in salivary cortisol, and 73.3% of leukemia survivors showed high sensitivity according to % suppression after oral dexamethasone (p<0.05). Serum cortisol at baseline, after the test, % suppression after intravenous dexamethasone, and the percentage of high sensitivity were reduced in the leukemia group (%F=36.7; p<0.05). The BcI1-NR3C1 and A3669G polymorphisms were present in 11/30 (36.7%) and 5/30 (16.7%) patients, respectively. GR-α mRNA levels were lower in the leukemia group than in the controls (p<0.05). Survivors of acute lymphoblastic leukemia presented with reduced glucocorticoid sensitivity. Glucocorticoid sensitivity allows individualized treatment to avoid adverse effects and may be involved in cardiovascular disease risk among this particular group of cancer survivors.