The Thoracoscore mortality risk model has been incorporated into the British Thoracic Society guidelines on the radical management of patients with lung cancer. The discriminative and predictive ability to predict mortality and post-operative pulmonary complications (PPCs) in this group of patients is uncertain. A prospective observational study was carried out on all patients following lung resection via thoracotomy in a regional thoracic centre over 42 months. 128 out of 703 subjects developed a PPC. 16 (2%) patients died in hospital. In a logistic regression analysis the Thoracoscore was not a significant predictor of mortality (OR 1.07, 95% CI 0.99-1.17; p=0.11) but was a significant predictor of PPCs (OR 1.08, 95% CI 1.03-1.13; p=0.002). However, the area under the receiver operator characteristic curve for the Thoracoscore was 0.68 (95% CI 0.56-0.80) for predicting mortality and 0.64 (95% CI 0.59-0.69) for PPCs, indicating limited discriminative ability. In a logistic regression analysis, another risk model, the European Society Objective Score, was predictive of mortality (OR 1.43, 95% CI 1.11-1.83; p=0.006) and PPCs (OR 1.48, 95% CI 1.30-1.68; p<0.0001). Therefore, Thoracoscore may have poor discriminative and predictive ability for mortality and PPCs following elective lung resection.