Clinical investigation of obesity-related risk factors aids in the early detection, prevention, and management of obesity. We aimed to examine the association between obesity and serum uric acid (sUA). A cross-sectional study was conducted including 18473 subjects from the National Health and Nutrition Examination Survey (NHANES). The exposure and outcome variables were sUA and body mass index (BMI), respectively. The weighted multivariate linear regression models and smooth curve fittings were conducted to assess the association between sUA and BMI. There were significantly positive correlations between sUA and BMI in both males and females (β = 1.414, 95% CI: 1.323-1.505, P < .0001, β = 1.853, 95% CI: 1.740-1.966, P < .0001, respectively). Furthermore, individuals in the higher sUA quartiles had higher BMI than those in the lowest quartile in both males and females. Subgroup analyses were stratified by race/ethnicity, results indicated the positive association of sUA with BMI in males remained in all races including Mexican American (β = 1.203, 95% CI: 0.965-1.442, P < .0001), other Hispanic (β = 1.126, 95% CI: 0.858-1.395, P < .0001), non-Hispanic White (β = 1.493, 95% CI: 1.343-1.642, P < .0001), non-Hispanic Black (β = 1.331, 95% CI: 1.122-1.540, P < .0001), and other races (β = 1.329, 95% CI: 1.115-1.544, P < .0001). And the positive association of sUA with BMI in females also remained in all races including Mexican American (β = 1.806, 95% CI: 1.520-2.092, P < .0001), other Hispanic (β = 2.033, 95% CI: 1.687-2.379, P < .0001), non-Hispanic White (β = 1.847, 95% CI: 1.657-2.037, P < .0001), non-Hispanic Black (β = 2.141, 95% CI: 1.874-2.408, P < .0001), and other races (β = 1.348, 95% CI: 1.081-1.615, P < .0001). The current cross-sectional study with 18473 US participants found that an elevated sUA was positively correlated with a higher BMI in males, females, and all kinds of races.Copyright © 2022 the Author(s). Published by Wolters Kluwer Health, Inc.