Purpose:The predictive factors of adrenal insufficiency after a prolonged, continuous course of corticosteroids is poorly documented. We evaluated it retrospectively in our department of endocrinology. Methods:The patients were included between January 2015 to January 2017 and were administered a Synacthene? 250 ug test (ST250) after substitution with hydrocortisone for at least 4 to 6 weeks. A non-responsive test was defined by a cortisol increase below 21ug/dL, 60 min after stimulation. We studied the risk factors associated with biological adrenal insufficiency by SPSS analysis. Results:sixty seven patients were included (mean age: 42 ? 13,10 years). Mean initial dose of corticosteroids was 41,95 ? 34,16 mg/d. forty-three patients failed to respond to the ST250. The comparison between the responder group and the non-responder group at TS250 showed that the difference is significant for the basal cortisol level (p= 0,016) and for the duration of the CTC (p=0.045). Conclusion:Biological adrenal insufficiency is very common after a prolonged course of corticosteroids. Hence, clinicians should be vigilant for adrenal insufficiency at all degrees of glucocorticoid exposure.