Abstract Introduction A permanent pacemaker is not rare in patients who undergo coronary artery bypass grafting (CABG). It is unknown if the presence of a pacemaker influences the long-term prognosis after surgery. Purpose To investigate if patients with permanent pacemaker have a higher risk for severe complications after CABG. Methods All patients who underwent CABG in Sweden 2006-2020 were included in a nationwide observational study based on prospectively collected data. Exclusion criteria were implantation of a cardioverter defibrillator at any time (prior to or after surgery) and death within 30 days. Individual patient data was merged from SWEDEHEART, The Swedish ICD- and pacemaker registry, the Cause of Death Register and the National Patient Register. Multivariable Cox regressions models were used to obtain hazard ratios (HR) with 95% confidence intervals (95%CI). The model was adjusted for age at operation, sex, left ventricular ejection fraction, heart failure, previous myocardial infarction, diabetes, peripheral artery disease, chronic respiratory disease, hypertension and atrial fibrillation. Results In total 41,722 patients underwent CABG during the study period, 555 (1.3%) of these had a previously implanted permanent pacemaker. Patients with a previous pacemaker were older, more often male, and had more often reduced left ventricular ejection fraction heart failure, atrial fibrillation, diabetes, hypertension and peripheral artery disease. Permanent pacemaker was not associated with higher risk for all-cause mortality (adjusted HR (aHR) 1.09 (95%CI=0.96-1.26), p=0.30, Figure 1), myocardial infarction (aHR: 1.01 (95%CI=0.73-1.41), p=0.94), or cardiovascular mortality (HR: 1.19 (95%CI=0.98-1.44), p=0.082). However, permanent pacemaker implantation was associated with increased risk for heart failure hospitalization (HR: 2.16 (95%CI=1.84-2.53), p<0.001). Conclusions A permanent pacemaker before CABG is not associated with increased mortality, cardiovascular mortality nor new myocardial infarction, but an increased risk for heart failure hospitalization after CABG. These patients could benefit from increased surveillance for heart failure symptoms after surgery to prevent hospitalizations.