The main indications for cervical mediastinoscopy are preoperative staging of lung cancer and diagnostic biopsy of mediastinal mass (lymphoma, sarcoidosis, tuberculosis etc.). We undertook a retrospective review of our experience of mediastinal exploration by cervical media-stinoscopy: 253 mediastinoscopies were performed on 252 patients (195 male and 57 female; mean age 53 years, range 14-88 years) between 1995 and June 2003. Four extended mediastinoscopies were performed and 1 patient had a re-mediastinoscopy following a non-diagnostic procedure. 319 lymph nodal stations were investigated in 253 procedures. We observed no mortality, while 2 patients had major bleeding (0.7%), with the need for open surgical treatment in order to achieve haemostasis. The median length of hospital-stay was one day, with discharge in the first postoperative day. 69 out of 170 patients, who eventually resulted to be affected by a histologically proven lung cancer, had a negative mediastinoscopy. Fifteen of them resulted N2 at the time of surgery: 8 patients with a false negativity in a biopsied station (4 in station 4R and 4 in station 7), while 7 cases showed infiltration in stations which were not sampled (5 in station 5, 1 in station 8 and 1 in station 7, the latter being the only one in which a standard cervical mediastincoscopy could have been able to stage it correctly). So, having observed 61 true negatives and 8 false-negatives in the sampled stations, in our experience the negative predictive value of cervical mediastinoscopy was 88.4%, with 78.2% of patients correctly staged without using other diagnostic tools. In conclusion, mediastinoscopy is an important procedure for the diagnostic biopsy of mediastinal mass and a useful tool in preoperative staging of lung cancer, especially if associated with chest CT-scan and Positron Emission Tomography (PET). In our experience, the spreading of PET does not lead to a reduction of cervical mediastinoscopies, both for the contemporary introduction of new chemotherapeutic preoperative protocols and, above all, for the not negligible incidence of false-positive results using PET, suggesting that media-stinoscopy should always be performed in patients affected by a PET-positive mediastinal growth.