Acute pulmonary exacerbation (APE) in CF is characterized by increased pulmonary symptoms attributed to an increase in inflammation. Antimicrobials, airway clearance and nutritional support remain the mainstay of therapy. However, when patients fail to improve, corticosteroids have been reported as an adjunct therapy. We retrospectively examined the use of rescue steroids in a children’s hospital during CF APE following at least one week of inpatient therapy without expected improvement from 2013 - 2017. 106 encounters, of 53 unique patients: aged 6-20 years; who had FEV1 percent predicted (FEV1pp) data at baseline, admission, midpoint, and discharge; and had admission duration of at least 12 days were studied. Encounters treated with steroids had less improvement at midpoint percent change from admission in FEV1pp (4.9, ±11.3) than admissions not given steroids change in FEV1pp=20.1, ±24.6; p-value<0.001. Failure to improve as expected was documented 98% of the time as the rationale for steroid use. At discharge, there was no difference in mean FEV1pp (p=0.76). Propensity matching was also evaluated and revealed no difference in admission, midpoint, or discharge FEV1pp between groups. Equally, no difference in FEV1pp at follow-up visit or in time until next APE was detected between groups. Moreover, delay in steroid therapy by waiting until the end of the second week increased length of stay. Secondary analysis for associations including gender, genotype, fungal colonization, or inhaled antimicrobials were non-significant. Our data suggest rescue use of corticosteroids during APE does not predictably impact important outcome measures in CF APE.