Introduction Perioperative medication in cardiac surgery recommends β-blockers’ use but it is not clear if its prescription should be started before or after cardiac surgery. Objectives To determine the effect of preoperative β-blocker therapy in long-term survival and postoperative complications after coronary artery bypass grafting surgery (CABG). Also, to study if recent acute myocardial infarction (AMI) changes this therapeutic effect. Materials and Methods Retrospective single-center study including consecutive patients submitted to first isolated CABG in 2006-2007. Data was collected through clinical files and informatic databases. Patients were grouped according to their preoperative Bblocker regimen: without (noBB) or with β-blockers (BB). Chi-square, independent t-tests, Kaplan- -Meier curves, Log Rank test and multivariable Cox regression were used. The mean follow-up time was 10 years, maximum 13 years. Results We included 562 patients, 468 (83%) were on preoperative β-blocker therapy. BB patients were younger (63±10 vs. 66±11, p=0.01) and predominantly male (79% vs. 75%, p=0.30). Recent myocardial infarction occurred in 46% BB vs. 53% noBB, (p=0.23) and BB patients presented less frequently moderate to severe left ventricular dysfunction (19% vs. 32%, p<0.01), history of stroke or transient ischemic attack (5% vs. 11%, p=0.04) and were less often in preoperative critical state (3% vs. 9%, p=0.01). Kaplan- -Meier analysis showed an improvement in cumulative survival in BB group (13-years survival: 66% vs. 57%, Log- -rank, p=0.01). After stratification by preoperative recent AMI occurrence, patients in BB group had better cumulative survival within patients with recent AMI (63% vs. 48%, Log-rank test p<0.01, BB vs. noBB, respectively), while preoperative β-blocker therapy had no impact on 13 years' survival in patients without recent AMI (70% vs. 67%, Log- -rank test p=0.73). After multivariable Cox regression, preoperative β-blocker therapy emerged as a protective agent (HR: 0.56, 95% CI: 0.39-0.81, p<0.01). This effect is maintained in patients with recent AMI (n=267, HR: 0.38, 95% CI: 0.22-0.65, p<0.01) but lost significance in patients without this event (n=295, HR: 0.99 95% CI: 0.55-1.80, p=0.98). There were no significant differences in postoperative complications. Conclusions In this study, β-blocker therapy showed a beneficial effect on long-term survival, particularly in patients with recent AMI. However, we consider that subsequent studies should be performed in order to elaborate more solid conclusions. As has been previously reported in literature, morbidity and mortality after isolated tricuspid surgery are high, with an increased rate of death at first year after surgery. Hypertension, cardiac dysfunction and diabetes mellitus are predictors of poor outcomes.