Background: Cardiovascular diseases increase the mortality risk in Graves’ disease (GD) patients. Atrial fibrillation (AF) is one of the most prevalent cardiovascular diseases in GD. Hyperthyroidism that occurs in GD may increase uric acid levels, while uric acid levels can also increase the risk of AF in the general population. This study is designed to observe the correlation between free T4 (FT4) and uric acid, and compare of uric acid in subjects with and without AF in GD. Methods: A cross-sectional study was conducted, including GD patients who met research criteria in Dr. Cipto Mangunkusumo Hospital during 2024. We performed history taking, physical examination, laboratory examination, and electrocardiogram for each subject. Data was analyzed using Pearson or Spearman correlation, and bivariate analysis to evaluate the comparison of uric acid in subjects with and without AF. Results: We included 74 subjects, with an average age was 41 years, mostly female (86.5%), and 62.2% had normal FT4 levels. AF occurred only in 4.1% subjects. Mean of uric acid is 4.71 ± 1.2 mg/dl, which is within the normal range. No correlation was found between FT4 and uric acid (r = 0.076; p = 0.520), including after adjustment with subgroup analysis based on thyroid status, gender, and diabetes mellitus. Mean of uric acid is not statistically different between subjects with and without AF (4.9 ± 1.01 mg/dl vs 4.7 ± 1.2 mg/dl; p = 0.785). Conclusion: No significant correlation was found between FT4 and uric acid. Mean of uric acid is not statistically different between subjects with and without AF. © 2025, Indonesian Society of Internal Medicine. All rights reserved.