Despite the efficacy of corticosteroid therapy, patients hospitalized for asthma exacerbations are at high risk for re-exacerbation and death after discharge. The objective of this prospective cohort study was to evaluate adherence to inhaled corticosteroids (ICS) and oral corticosteroids (OCS) after discharge in adults hospitalized for asthma exacerbations. ICS and OCS were equipped with electronic medication monitors and were provided at discharge. Adherence (use/prescribed use x 100%) was measured by self-report and canister weight (ICS), pill count (OCS), and electronic medication monitors (both ICS and OCS) 2 weeks after discharge. Poor adherence was defined as adherence of less than 50%. The Asthma Control Questionnaire was used to assess symptom control. Sixty patients were enrolled (age 42.2 years, 98.3% African American, 65.0% female, 46.7% with history of near-fatal asthma). Electronically measured adherence to both corticosteroids dropped to approximately 50% within 7 days of discharge. Poor adherence to both corticosteroids predicted significantly worse symptom control (p = 0.04). Self-report, canister weight, and pill count all had low sensitivity (29.2%, 65.0%, and 7.7%, respectively) for detecting poor adherence. We conclude that adherence to ICS and OCS deteriorates within days of hospital discharge but may not be recognized in a substantial proportion of patients.