Introduction: Elevated Lp(a) is associated with atherosclerotic, thrombotic, and proinflammatory effects. In patients with prior coronary artery bypass grafting (CABG), graft failure and progression of native CAD are associated with adverse outcomes. We sought to evaluate the relationship between Lp(a) and adverse cardiovascular events in patients with prior CABG.Methods: We included all patients with prior CABG from a large, contemporary Lp(a) registry. Cox proportional hazard models were used to estimate the association between repeat coronary revascularization (CR) - defined as percutaneous coronary intervention (PCI) or repeat CABG - as well as incident MI or CV death, stratified by tertiles of Lp(a).Results: Among the 16,419 individuals in the cohort, 878 (5.3%) patients (23.4% women, median age 66) had CABG prior to their Lp(a) test date. Among those with prior CABG, 81.7% had hypertension, 87.9% had hyperlipidemia, and 42.1% had diabetes. Patients with prior CABG had higher Lp(a) levels (46.3 nmol/L [IQR 15.8-148]) than with those without prior CABG (35 nmol/L [IQR 13-111.7]). Over a median follow-up of 11.2 years, patients in the highest Lp(a) tertile [>= 95 nmol/L] were more likely to undergo repeat CR (HR 1.86 (95% CI, 1.18-2.94), p=0.008) with PCI (n=83), repeat CABG (n=5), or both CABG and PCI (n=12). This association persisted when adjusted for age, sex, race, diabetes, and hypertension (HR 1.67 (95% CI,1.05-2.67). Additionally, patients in the highest Lp(a) tertile were more likely to experience CV death or MI (HR 1.56 (95% CI, 1.17-2.08); this increased risk persisted in adjusted analyses (HR 1.59 (95% CI,1.19-2.14) (see Figure 1).Conclusions: Among patients with prior CABG, elevated Lp(a) is associated with a higher risk of repeat coronary revascularization and adverse CV events. Future studies should focus on the potential role of Lp(a) lowering therapies for maintaining graft patency and reducing CV events.