Background: In 2019 a record number of patients were admitted to our children’s hospital with e-cigarette or vaping-associated lung injury (EVALI). The majority of patients were treated with high-dose prednisone therapy including 3 days of 1000 mg daily followed by a 4 week wean. Because of the concern for iatrogenic adrenal insufficiency, all patients were then placed on a 3-4 weak hydrocortisone taper followed by ACTH stimulation testing. The purpose of this study is to document the incidence of iatrogenic adrenal insufficiency following a 2 months glucocorticoid wean. Methods: All patients seen by the Pulmonary team for EVALI who also received high dose prednisone therapy were referred to Pediatric Endocrinology for ACTH testing. A low dose (1 mcg) ACTH stimulation test was performed with cortisol measurements at baseline, 30 minutes, and 60 minutes. A passing result was any cortisol over 18 ug/dl. Results: An anticipated 20-25 patients will have had ACTH stimulation testing by the time of abstract presentation. Of those that have already completed testing, three of four patients failed the first time. Discussion: High-dose prednisone therapy for EVALI is associated with significant rates of iatrogenic adrenal insufficiency, even after slow hydrocortisone wean. Structures need to be implemented to teach patients about adrenal insufficiency prior to hospital discharge and organize adequate post-discharge follow-up until HPA function returns.