Background: People with renal disease have a markedly higher risk of cardiovascular disease as well as morbidity and mortality after cardiac surgery. Little is known regarding the post-operative adverse outcomes following isolated coronary artery bypass graft (CABG) in the Australian population with renal disease. Objectives: The aim of this study was to examine the effect of different stages of renal disease on patients' risk of post-operative mortality and complications following isolated CABG in an Australian cohort. Methods: Using the ANZSCTS (Australian and New Zealand Society of Cardiac and Thoracic Surgeons) registry, data from 44,968 patients who underwent isolated CABG between 2001 and 2014 were used. The effect of renal disease stages on short- and long-term outcomes were examined using multivariable logistic and Cox's regression methods respectively. Results: Three of 4 Australian patients (74.6%) who underwent isolated CABG had some degree of renal disease: 50.2% mild; 20.9% moderate; 2.1% severe; and 1.6% dialysis-dependent. Adjusted risk of 30-day mortality increased with deteriorating renal disease from mild (1.6-fold) to dialysis-dependent (4.6-fold). Worsening renal disease was also associated with higher risk of post-operative complications. Hazard ratio for long-term survival shows steady increase of mortality risk with worsening renal disease categories from 1.1-fold for mild to 3.9-fold for patients on dialysis. Conclusions: Pre-existing renal disease is significantly associated with 30-day and long-term mortality, length of intensive care unit and hospital stay as well as several other post-operative complications.