Background: Galactin is involved in process of cardiac fibrosis. It is not clear if there is an association between serum galactin level and thromboembolism events in atrial fibrillation (AF). Objective: To investigate whether serum galactin levels can be used as a predictor for thromboembolism in patients with non-valvular AF or not. Patients and Methods: We conducted a case-control study on 200 participants (100 individuals as a control, 50 patients with AF and thromboembolism and 50 patients with AF but without thromboembolism). We recruited patients from Cardiology Department, Aswan University Hospital who had non valvular AF. Participants were subjected to detailed medical history, clinical examination, electrocardiography, and ELISA test to evaluate serum galactin level. Results: Serum galactin was only predictor for thromboembolic event (OR=2.4, 95% CI = {1.3: 4.3}, P value=0.005) with a sensitivity of 73% and specificity of 65% for the thrombus detection (AUC= 0.80, 95%CI= {0.69-0.89}). Serum galactin has a sensitivity of 81% and specificity of 77% to detect AF incidence (AUC= 0.84, 95%CI= {0.73-0.99}). Serum galactin was correlated to CHADS-VASc score (r= 0.75, p value < 0.001) and LVEF (r= - 0.586, p value <0.001). Conclusion: Galactin-3 level is a possible predictor for thromboembolism in patients with non-valvular AF. Nevertheless, further studies are still needed to confirm our findings.