Many adults with atherosclerotic cardiovascular disease (ASCVD) who are recommended to take a statin, ezetimibe and/or a proprotein convertase subtilisin/kexin type 9 inhibitor (PCSK9i) by the 2018 American Heart Association/American College of Cardiology cholesterol guideline do not receive these medications. We estimated the percentage of recurrent ASCVD events potentially prevented with guideline-recommended cholesterol-lowering therapy following a myocardial infarction (MI) hospitalization. We conducted simulations using data from US adults with government health insurance through Medicare or commercial health insurance in the MarketScan database. We used data from patients with an MI hospitalization in 2018-2019 to estimate the percentage receiving guideline-recommended therapy. We used data from patients with an MI hospitalization in 2013-2016 to estimate the 3-year cumulative incidence of recurrent ASCVD events (i.e., MI, coronary revascularization or ischemic stroke). The low-density lipoprotein cholesterol (LDL-C) reduction with guideline-recommended therapy was derived from trials of statins, ezetimibe and PCSK9i, and the associated ASCVD risk reduction was estimated from a meta-analysis by the Cholesterol-Lowering Treatment Trialists Collaboration. Among 279,395 patients with an MI hospitalization in 2018-2019 (mean age 75years, mean LDL-C 92mg/dL), 27.3% were receiving guideline-recommended cholesterol-lowering therapy. With current cholesterol-lowering therapy use, 25.3% (95%CI: 25.2%-25.4%) of patients had an ASCVD event over 3years. If all patients were to receive guideline-recommended therapy, 19.8% (95%CI: 19.5%-19.9%) were estimated to have an ASCVD event over 3years, representing a 21.6% (95%CI: 20.5%-23.6%) relative risk reduction. Implementation of guideline-recommended cholesterol-lowering therapy could prevent a substantial percentage of recurrent ASCVD events.