Central to risk assessment for lung resection is the fact that surgery offers the only chance of long-term survival and cure in non-small carcinoma of the lung. The challenge is, therefore, to offer surgery to as many patients as possible, whilst avoiding the risk of death from postoperative respiratory failure. Risk assessment is based on careful evaluation of the patient's existing cardiac and respiratory disease. The use of a cardiac risk index, such as that described by Detsky, will ensure that cardiac risk factors are recognised and, where possible, ameliorated prior to surgery. Pre-existing respiratory disease may be assessed by arterial blood gas analysis, exercise testing, whole and regional lung function tests. Criteria based on these tests have been proposed to aid patient selection prior to lung resection. However, these criteria take no account of the beneficial influence on outcome of modern anaesthesia and postoperative care. The elimination of postoperative pain, along with techniques such as minitracheostomy and incentive spirometry have allowed surgery to be offered to many patients who would have been deemed unsuitable by standard criteria. Patients with potentially resectable lung cancer must never be arbitrarily excluded from surgery on the basis of any single criteria or test. Referral for assessment by an experienced team consisting of a thoracic physician, surgeon and anaesthetist will maximise the number of patients offered surgery for this otherwise incurable disease.