BACKGROUND: Antimicrobial stewardship programs (ASPs) promote the principle of de-escalation: moving from broad to narrow spectrum agents and stopping antibiotics when no longer indicated. A standard, objective definition of de-escalation applied to electronic data could be useful for ASP assessments. METHODS: We derived an electronic definition of antibiotic de-escalation and performed a retrospective study among five hospitals. Antibiotics were ranked into 4 categories: narrow spectrum, broad spectrum, extended spectrum, and agents targeted for protection. Eligible adult patients were cared for on inpatient units, had antibiotic therapy for at least 2 days, and were hospitalized for at least 3 days after starting antibiotics. Number of antibiotics and rank were assessed at two time points: day of antibiotic initiation and either day of discharge or day 5. De-escalation was defined as reduction in either the number of antibiotics or rank. Escalation was an increase in either number or rank. Unchanged was either no change or discordant directions of change. We summarized outcomes among hospitals, units, and diagnoses. RESULTS: Among 39,226 eligible admissions, de-escalation occurred in 14,138 (36%), escalation in 5,129 (13%), and antibiotics were unchanged in 19,959 (51%). De-escalation varied among hospitals (median 37%, range 31-39%, p<.001). Diagnoses with lower de-escalation rates included intra-abdominal (23%) and skin and soft tissue (28%) infections. Critical care had higher rates of both de-escalation and escalation compared with wards. CONCLUSIONS: Our electronic de-escalation metric demonstrated variation among hospitals, units, and diagnoses. This metric may be useful for assessing stewardship opportunities and impact.