Objective To investigate the association between body roundness index (BRI) and urge urinary incontinence (UUI) in a nationally representative U.S.population, so as to provide a new indicator for the prevention and management of UUI. Methods A total of 17226 participants from the 2015—2023 National Health and Nutrition Examination Survey (NHANES) were included in the study. The association between BRI and UUI was assessed with weighted multivariable logistic regression, and the nonlinear relationship was analyzed with weighted restricted cubic spline (RCS). Subgroup analyses were conducted based on demographic and clinical characteristics to explore potential heterogeneity in the association. Receiver operating characteristic (ROC) curves were plotted to compare the predictive performance of BRI with body mass index (BMI) and waist circumference for UUI, and the area under the curve (AUC) was calculated. Results A total of 4879 UUI patients (28.32%, UUI group) and 12347 non UUI participants (71.68%, NUUI group) were included in the 17226 participants. Significant differences were observed between the UUI and NUUI groups in terms of age, sex, race, marital status, BIM, height, waist circumference, poverty income ratio (PIR), diabetes, alcohol consumption and smoking (P<0.001). The participants in the UUI group had significantly higher BRI than that in the NUUI group [ (6.53±2.63) vs. (5.47±2.34), P<0.001]. As BRI increased from Q2 to Q4, the incidence of UUI also rose (P_(trend)<0.0001). After the confounding factors were fully adjusted, participants in the Q4 group had a 104% increased risk of UUI compared to the Q1 group (OR=2.04, 95% CI:1.81-2.30, P<0.0001). There was a significant positive nonlinear trend in the dose-response relationship between UUI and BRI (P_(overall trend)<0.001, P_(nonlinear association)=0.886). Subgroup analysis showed that the association between UUI and BRI was more significant in diabetic patients, different racial and BMI stratifications (P<0.05).ROC curve analysis showed that, compared with BMI (AUC=0.59) and waist circumference (AUC=0.59), BRI demonstrated superior predictive accuracy (AUC=0.63, P<0.001). Conclusion Based on US 2015—2023 NHANES, the study shows that increased BRI is independently associated with an increased risk of UUI, and its predictive performance is superior to traditional obesity metrics.BRI has the potential to serve as a risk stratification tool for UUI.