Study objective:The 2018 American Heart Association/American College of Cardiology (AHA/ACC) cholesterol guideline recommends a maximally-tolerated statin with add-on lipid-lowering therapy, ezetimibe and/or proprotein convertase subtilisin/kexin type 9 (PCSK9) for adults with very-high atherosclerotic cardiovascular disease (ASCVD) risk to achieve a low-density lipoprotein cholesterol (LDL-C) <70 mg/dL. We estimated the percentage of US adults with ASCVD recommended, by the 2018 AHA/ACC cholesterol guideline, and receiving add-on lipid-lowering therapy.Design, setting, and participants:Cross-sectional study including 805 participants from the US National Health and Nutrition Examination Survey (NHANES) 2013–2020 data. NHANES sampling weights were used to obtain estimates for the US adult population.Main measures:Very-high ASCVD risk was defined as either: ≥2 ASCVD events, or one ASCVD event with ≥2 high-risk conditions. Being recommended add-on lipid-lowering therapy was defined as having very-high ASCVD risk and LDL-C ≥ 70 mg/dL, or LDL-C < 70 mg/dL while taking ezetimibe or a PCSK9 inhibitor.Results:An estimated 18.7 (95%CI, 16.0–21.4) million US adults had ASCVD, of whom 81.6 % (95%CI, 76.7 %−86.4 %) had very-high ASCVD risk, and 60.1 % (95%CI, 54.5 %–65.7 %) had very-high ASCVD risk and LDL-C ≥ 70 mg/dL. Overall, 61.4 % (95%CI, 55.8 %–66.9 %) were recommended add-on lipid-lowering therapy and 3.2 % (95 % CI, 1.2 %–5.3 %) were taking it. Smokers, adults with diabetes, hypertension and chronic kidney disease were more likely, while those taking atorvastatin or rosuvastatin were less likely, to be recommended add-on lipid-lowering therapy.Conclusion:The majority of US adults with ASCVD are recommended add-on lipid-lowering therapy by the 2018 AHA/ACC cholesterol guideline but few are receiving it.