The exact indications for computed tomography (CT) of the thorax and mediastinoscopy (MS) in lung cancer still remain incompletely defined. The present study was designed to establish a standard approach to cervical MS for otolaryngologists, who in Denmark are traditionally involved in the staging of non-small-cell lung cancer (NSCLC). Sixty-four potentially operable patients with NSCLC underwent thoracic CT prior to bronchoscopy and cervical MS. Cervical MS alone established the histological diagnosis in 20% of the patients. In diagnosing lymph node metastases in the superior mediastinum, a criterion of 10 mm for abnormal enlargement resulted in an overall sensitivity and specificity of mediastinal CT of 81 and 84%, respectively, and the overall false-negative and false-positive rates appeared to be 10 and 29%, respectively. It could be demonstrated that mediastinal lymph nodes in patients with mediastinal metastases were significantly larger than mediastinal lymph nodes in patients without metastases. No clinicopathological characteristics could be identified to influence the accuracy of CT, except for the finding that the rate of false-negative mediastinal CT was significantly higher in patients with right-sided than in patients with left-sided lesions. It is concluded that because of the relatively low sensitivity and specificity of mediastinal CT, cervical MS remains essential in the evaluation of patients with presumed or verified NSCLC and that cervical MS, in experienced hands, is a safe and accurate procedure. For Danish otolaryngologists, the strategy of routine cervical MS, performed under general anaesthesia in the same stage as bronchoscopy, is advocated as a standard approach to mediastinal assessment for the staging of NSCLC. However, thoraco-abdominal CT is advocated for all patients with NSCLC, in whom operation is contemplated, as a supplementary investigation after other routine diagnostic and staging procedures, including cervical MS, have been carried out.