Objective: Atrial structural remodeling has been suggested to contribute to atrial fibrillation (AF) recurrence following direct-current cardioversion (DCCV). The role of several inflammatory and extracellular matrix turnover markers in AF recurrence following DCCV has been investigated. However, data on the impact of galectin-3, which is known to play a role in various fibrotic conditions, including cardiac fibrosis are lacking. The aim of this study was to demonstrate the predictive role of serum galectin-3 levels in AF recurrence following successful DCCV. Methods: A total of 90 persistent AF patients who were scheduled for DCCV were prospectively enrolled. Serum samples were assayed to determine pre-DCCV galectin-3 levels using the enzyme-linked immunosorbent assay method. Patients were followed up for 3 months for AF recurrence. Results: Of 90 persistent AF patients (mean age: 55.33±7.94 years; 53.33% male) who underwent successful DCCV, 28 (31.11%) experienced early AF recurrence within 3 months. Patients with AF recurrence had a greater left atrial volume index (LAVI) (33.35± 2.45 mL/m2 vs. 29.21±3.08 mL/m2; p<0.001) and serum galectin-3 levels were higher (0.88 ng/mL [min-max: 0.52-1.32] vs. 0.60 ng/mL [min-max: 0.38-0.91]; p<0.001). In multivariate analysis, the number of DCCV attempts (hazard ratio [HR]: 1.879, 95% confidence interval [CI]: 1.052-3.355; p=0.033), LAVI (HR: 1.180, 95% CI: 1.028-1.354; p=0.018), and serum galectin-3 level (HR: 11.933, 95% CI: 1.220-116.701; p=0.033) were found to be independently associated with early AF recurrence following successful DCCV. Conclusion: Circulating levels of galectin-3 may have an association with early AF recurrence following DCCV.