BACKGROUND Atrial flutter (AFL) is a common arrhythmia associ-ated with significant morbidity, yet the incremental burden of this condition has not been well documented. OBJECTIVE Using real-world data, we sought to evaluate the healthcare use and cost burden of incident AFL in the United States METHODS From 2017 to 2020, persons with an incident diagnosis of AFL were identified through Optum Clinformatics, a nationally representative administrative claims database of commercially insured individuals in the United States. We constructed 2 cohorts (AFL patient; non-AFL comparator) and used a matching weights method to balance covariates between cohorts. Using logistic regression and general linear models, 12-month all-cause and car-diovascular (CV)-related health care use (inpatient, outpatient, emergency room [ER] visits, and other) as well as medical expendi-tures were compared between the matched cohorts. RESULTS The matching weight sample sizes were 13,270 for AFL and 13,683 for the non-AFL cohorts. In the AFL cohort, w71% were at least 70 years of age, 62% identified as male, and 78% iden-tified as White. The AFL cohort had significantly higher health care use, including all-cause (relative risk [RR] 1.14; 95% confidence in-terval [CI] 1.11-1.18) and CV-related ER visits (RR 1.60; 95% CI 1.52-1.70) compared with the non-AFL cohort. Mean total health care costs (per patient annually) were almost $21,783 (95% CI $18,967-$24,599) higher among patients with AFL compared to those without AFL ($71,201 vs $49,418, respectively; P ,.001). CONCLUSION Amidst the backdrop of an aging population, find-ings from this study draw attention to the importance of timely and adequate treatment of AFL.