BACKGROUND: We explored the link between sST2 and NT-proBNP levels and postoperative atrial fibrillation (POAF) incidence in non-cardiac surgery patients in this study. METHODS: The research involved 302 participants over 40 years old who underwent medium and/or high-risk noncardiac surgeries. These patients were divided into two groups: those who developed POAF and those who did not. RESULTS: The study cohort consisted of a total of 302 patients, with 14 (4.6%) experiencing POAF. POAF was more common in patients with previous heart failure, a high Left Atrial Volume Index (LAVI), and elevated ASA and RCRI scores (all P<0.05). LAVI, sST2, NT-proBNP, and RCRI scores were found to be independent predictors of POAF in patients undergoing non-cardiac surgeries (all P<0.05). The area under the curve (AUC) for sST2 and NT-proBNP in predicting POAF was 0.707 (95% CI 0.544-0.869; P=0.009) and 0.727 (95% CI 0.598-0.857; P=0.004), respectively. Combined elevation of sST2 and NT-proBNP increased the likelihood of developing POAF by approximately 8.5 times (OR: 8.65, CI 95% 1.06-35.3, P=0.044). CONCLUSIONS: sST2 and NT-proBNP are valuable predictors of POAF in patients undergoing non-cardiac surgery. Identifying these predictors can help in recognizing high-risk patient groups for POAF.