Background Influenza vaccination protects against morbidity and mortality in patients with cardiovascular disease (CVD). We aimed to describe influenza vaccine uptake in patients with CVD in a universal-access healthcare system. Methods Using nationwide Danish registries, we included all patients with prevalent CVD, defined as heart failure (HF), atrial fibrillation (AF), ischemic heart disease (IHD), or stroke during three consecutive influenza seasons (October-December 2017-2019). The outcome was relative frequency of influenza vaccination across strata of patient characteristics. Results There was an average of 397 346 patients with CVD yearly during 2017-2019. Vaccine uptake was 45.6% for the whole population and ranged from 55.0% in AF to 61.8% in HF among patients aged >= 65 years. Among patients aged