IMPORTANCE: Numerous studies have compared the results of on-pump and off-pump coronary artery bypass grafting (CABG), but little is known about how either the relative use of these procedures or their associated perioperative mortality have changed with time. OBJECTIVE: To examine trends in off- and on-pump CABG use and outcomes over time. DESIGN: Retrospective analysis of data from the Veterans Affairs Surgical Quality Improvement Program (VASQIP). SETTING: Data were collected from 42 Veterans Affairs cardiac surgery centers. PARTICIPANTS: All Veterans Affairs patients (n = 65 097) who underwent isolated primary CABG from October 1997 to April 2011. INTERVENTIONS: Patients underwent either on-pump (ON) or off-pump (OFF) CABG. MAIN OUTCOMES AND MEASURES: The percentages of ON vs OFF cases as a function of time. We also evaluated trends over time in rates of conversion from OFF to ON CABG, perioperative mortality (30-day or in-hospital), and VASQIP predicted risk of mortality. RESULTS: The relative use of OFF CABG peaked at 24% in 2003, followed by a slow and mostly consistent decline to stabilize at about 19%. The conversion rate decreased with time and has stayed less than 3.5% since 2007 (P < .001). Perioperative mortality rates decreased over time for both ON and OFF CABG (P < .001) and have stayed less than 2% for the entire cohort since 2006. The mortality associated with converted cases was high regardless of the surgery year and exceeded the VASQIP predicted risk of mortality. CONCLUSIONS AND RELEVANCE: There has been a decline in the relative use of OFF CABG in the Veterans Affairs system since 2003. This trend may affect the training of future generations in OFF surgery and influence conversion rates and outcomes. Copyright 2013 American Medical Association. All rights reserved.