Prophylactic intra-aortic balloon pumping prior to coronary artery bypass grafting is employed variably despite some evidence to support its use. The aim of this study was to describe the characteristics, preoperative balloon pump utilization, and outcomes of high-risk patients undergoing coronary artery bypass. The study cohort included all patients in the Australian National Cardiac Surgery Database over an 8 year period. The primary outcome was 30-day mortality adjusted for preoperative illness severity. Coronary artery bypass was performed in 18,662 patients including 2,348 (12.6%) identified as high-risk. Of these high-risk patients, 359 (15.3%) received a balloon pump preoperatively. For high-risk patients, 30-day mortality was significantly higher in those with a preoperative balloon pump than in those who did not receive a preoperative balloon pump (15.3% vs. 4.9%). After adjusting for preoperative illness severity, there was no significant association between preoperative balloon pumping and 30-day mortality. High-risk patients represent a significant proportion of those undergoing coronary artery bypass grafting. Despite their increased risk of postoperative mortality, only a small minority currently receive a preoperative balloon pump. After adjusting for illness severity, there was no significant association between preoperative balloon pumping and 30-day mortality, although we could not rule out a 20% reduction in mortality.