Background Prevalence of atrial fibrillation (AF) continues to increase and is associated with significant cardiovascular morbidity and mortality. To inform prevention strategies aimed at reducing the burden of AF, we sought to quantify trends in cardiovascular mortality related to AF in the United States. Methods and Results We performed serial cross‐sectional analyses of national death certificate data for cardiovascular mortality related to AF, whereby cardiovascular disease was listed as underlying cause of death and AF as multiple cause of death among adults aged 35 to 84 years using the Centers for Disease Control and Prevention's Wide‐Ranging Online Data for Epidemiologic Research. We calculated age‐adjusted mortality rates per 100 000 population and examined trends over time, estimating average annual percentage change using the Joinpoint Regression Program. Subgroup analyses were performed by race‐sex and across 2 age groups (younger: 35–64 years; older: 65–84 years). A total of 276 373 cardiovascular deaths related to AF were identified in the United States between 2011 and 2018 in decedents aged 35 to 84 years. Age‐adjusted mortality rate increased from 18.0 (95% CI, 17.8–18.2) to 22.3 (95% CI, 22.0–22.4) per 100 000 population between 2011 and 2018. The increase in age‐adjusted mortality rate (average annual percentage change) between 2011 and 2018 was greater among younger decedents (7.4% per year [95% CI, 6.8%–8.0%]) compared with older decedents (3.0% per year [95% CI, 2.6%–3.4%]). Conclusions Cardiovascular deaths related to AF are increasing, especially among younger adults, and warrant greater attention to prevention earlier in the life course.