Background: Preoperative risk status is a major factor influencing outcomes for patients undergoing isolated CABG. Using the Australasian Society of Cardiac and Thoracic Surgeons (ASCTS) Database, we have examined trends in preoperative risk profile and subsequent 30-day mortality for patients undergoing isolated CABG over the past five years. Methods: Nine thousand three hundred and seventy-two consecutive isolated CABG procedures collected from the six Victorian Public Hospitals between 1 July 2001 and 31 June 2006 were evaluated. Results:There is a trend towards an increase in the proportion of patients over the age of 80 years (p < 0.07), but there has been little change in overall age and gender (mean age 65 and 77% males) of patients undergoing CABG over the past 5 years. There has also been an increase in the proportion of patients with a history of smoking (p < 0.001), hypertension (p < 0.001), previous CABG (p < 0.001), previous myocardial infarction (p < 0.004), previous congestive heart failure (p < 0.06) and previous PTCA/stent (p < 0.09). The patients’ predicted preoperative risk remains similar over the past 5 years at 1.8% for CABG surgery. The overall mortality has ranged from 2.2% to 1.8% whilst there has been a significant decrease of 50% in mortality for elective procedures. Conclusion: Despite an increase in elderly patients, 30-day mortality has decreased over the past 5 years, in particular for elective CABG surgery.