OBJECTIVE To evaluate the impact of renal insufficiency (RI) on long-term mortality and incident myocardial infarction (MI) in patients undergoing coronary artery bypass grafting (CABG). RESULTS All patients (n = 6575) without dialysis-dependent RI undergoing a first isolated CABG during 1980-1995 at the Karolinska hospital who survived 30 days post-operatively were included. Estimated glomerular filtration rate (eGFR) was related to the incidence of MI and all-cause mortality within 5 years. There were 628 deaths and 496 incident MIs during follow-up. After multivariable adjustment, patients with mild (eGFR 60-90 mL/min), moderate (eGFR 30-60 mL/min), and severe (eGFR <30 mL/min) RI had an increased mortality within 5 years post-CABG; hazard ratio (HR) 1.2 [95% confidence interval (CI) 1.0-1.6], HR 1.8 (95% CI 1.3-2.4), and HR 5.2 (95% CI 3.1-8.6), respectively, compared with patients with normal renal function (eGFR >90 mL/min). In patients with moderate and severe RI, there was an increased incidence of MI; HR 1.5 (95% CI 1.1-2.1) and HR 3.5 (95% CI 1.8-6.8), respectively. There were no gender differences. CONCLUSIONS Already mild RI predicts late all-cause mortality after coronary artery bypass grafting (CABG), and moderate and severe RI is associated with an increased long-term incidence of MI post-CABG.