Aim: The Thoracic Revised Cardiac Risk Index (ThRCRI) is a cardiac risk stratification tool specific to patients undergoing thoracic surgery. However, its usage is not accepted in routine practice yet. In this study, we aimed to validate the reliability of ThRCRI for predicting cardiac complications in an independent cohort undergoing lung resections for non-small-cell lung cancer (NSCLC). Material and Method: Data of 249 patients were analyzed according to ThRCRI scores and cardiovascular complication rate. ROC analyses were also carried out to evaluate the reliability of ThRCRI categories. Results: Higher ThRCRI risk scores were found to be associated with higher overall cardiac complication rates (p<0.0001) with a moderate-to-high reliability. Discussion: This study externally validated the discriminative ability of ThRCRI to differentiate high-risk patients for major cardiac complications following major lung resections. We advocate its use as a cardiac screening tool for patients who are candidates for lung resection.