The frequency of lung cancers associated with synchronous head and neck malignancies can be evaluated between 1.5 to 2%. The purpose of our work was to determine if complete endoscopic head and neck examination performed under general anesthesia was superior than clinical head and neck examination for the diagnosis of these synchronous additional tumors. From july 1991 to august 1992, we realised a prospective study on 58 consecutive patients suffering from pulmonary removable lung cancers. All the patients had a clinical head and neck examination during the preoperative period. Immediately before thoracotomy a complete endoscopy of head and neck aerian and digestive tract was performed. During this last examination 18 new macroscopical lesions were discovered in 13 patients: benign lesions (n = 17), oral cavity and laryngeal dysplasia (n = 1). The one gingivolingual sulcus carcinoma, already discovered by the clinical examination, was confirmed. This study suggests that complete head and neck endoscopy is not superior than clinical examination for the diagnosis of synchronous malignancies before lung cancers removal.