OBJECTIVES: Treatment guidelines stipulate that clopidogrel should be interrupted ≥5 days prior to elective coronary artery bypass grafting (CABG) to reduce the risk of bleeding. However, if urgent CABG is indicated, experienced surgeons may perform CABG in <5 days. This study is the first to describe patterns of acute clopidogrel use and inpatient costs among acute coronary syndrome (ACS) patients undergoing CABG, which will help decision makers understand the relative benefits/costs of antiplatelet therapies in real-world practices. METHODS: The study used the MarketScan® Commercial, Medicare, and Hospital Drug Databases, comprising administrative healthcare data for over 63 million individuals. ACS episodes, defined as hospitalizations for ACS (primary ICD-9-CM diagnosis 410.xx, 411.1x), occurring between 1/1/2005-6/30/2009 were identified from patients aged ≥18 years. Outcomes included costs and lengths of stay (LOS) of ACS episodes with CABG and, among clopidogrel-treated patients, number of days between the day CABG was performed and the last clopidogrel dose administered. Analyses were descriptive. RESULTS: 160,168 ACS episodes were identified; mean patient age = 63.5 years.  CABG episodes comprised 9.3% (14,896/160,168) of ACS episodes. The mean LOS was 9.8 [SD 6.8] days per CABG episode. Mean inpatient costs were $71,140 [SD $68,012] per CABG episode. Among clopidogrel-treated patients with inpatient drug data who underwent CABG (n=8,101), the mean days between the day CABG was performed and the last dose of clopidogrel administered was 3.3 [SD 2.6] days and the majority (62.1%) underwent surgery within 2-3 days after their last clopidogrel dose. The mean incremental increase in inpatient costs associated with 1 extra LOS day was $1,950. CONCLUSIONS: Data suggest that surgeons commonly perform CABG within <5 days after clopidogrel administration. However, among patients for whom urgent CABG is not indicated, withholding CABG may only minimally affect inpatient costs and must be considered in the broader context of patient management.