Importance: Patients undergoing vascular surgery are at high risk of postoperative myocardial infarction (POMI). Postoperative myocardial infarction is independently associated with significant risk of in-hospital mortality. Objective: To examine the association of patient and procedural characteristics with the risk of POMI after vascular surgery and determine the association of evidence-based therapies with longer-term outcomes. Design, Setting, and Participants: A retrospective cohort study of prospectively collected data within a statewide quality improvement collaborative database between January 2012 and December 2017. Patient demographics, comorbid conditions, and perioperative medications were captured. Patients were grouped according to occurrence of POMI. Univariate analysis and logistic regression were used to identify factors associated with POMI. The collaborative collects data from private and academic hospitals in Michigan. Patients undergoing major vascular surgery, defined as endovascular aortic aneurysm repair, open abdominal aortic aneurysm, peripheral bypass, carotid endarterectomy, or carotid artery stenting were included. Analysis began December 2018. Main Outcomes and Measures: The presence of a POMI and 1-year mortality. Results: Of 26231 patients identified, 16989 (65.8%) were men and the overall mean (SD) age was 69.35 (9.89) years. A total of 410 individuals (1.6%) experienced a POMI. Factors associated with higher rates of POMI were age (odds ratio [OR], 1.032 [95% CI, 1.019-1.045]; P <.001), diabetes (OR, 1.514 [95% CI, 1.201-1.907]; P <.001), congestive heart failure (OR, 1.519 [95% CI, 1.163-1.983]; P =.002), valvular disease (OR, 1.447 [95% CI, 1.024-2.046]; P =.04), coronary artery disease (OR, 1.381 [95% CI, 1.058-1.803]; P =.02), and preoperative P2Y12 antagonist use (OR, 1.37 [95% CI, 1.08-1.725]; P =.009). Procedurally, open abdominal aortic aneurysm (OR, 4.53 [95% CI, 2.73-7.517]; P <.001) and peripheral bypass (OR, 2.375 [95% CI, 1.818-3.102]; P <.001) were associated with the highest risk of POMI. After POMI, patients were discharged and received evidence-based therapy with high fidelity, including β-blockade (296 [82.7%]) and antiplatelet therapy (336 [95.7%]). A high portion of patients with POMI were dead at 1 year compared with patients without POMI (113 [37.42%] vs 993 [5.05%]; χ2 = 589.3; P <.001). Conclusions and Relevance: Despite high rates of discharge with evidence-based therapies, the long-term burden of POMI is substantial, with a high mortality rate in the following year. Patients with diabetes mellitus, coronary artery disease, congestive heart failure, and valvular disease warrant additional consideration in the preoperative period. Further, aggressive strategies to treat patients who experience a POMI are needed to reduce the risk of postoperative mortality.