BACKGROUND The aim of the study is to analyze diagnostic yield of the new surgical technique--the Transcervical Extended Mediastinal Lymphadenectomy (TEMLA) in preoperative staging of Non-Small-Cell Lung Cancer (NSCLC). METHODS Operative technique included 5-8 cm collar incision in the neck, elevation of the sternal manubrium with a special retractor, bilateral visualization of the laryngeal recurrent and vagus nerves and dissection of all mediastinal nodal stations except of the pulmonary ligament nodes (station 9). RESULTS 698 patients (577 men, 121 women), of mean age 62.8 (41-79) were operated on from 1.1.2004 to 31.1.2010, including 501 squamous-cell carcinomas, 144 adenocarcinomas, 25 large cell carcinomas and 28 others. Mean operative time was 128 min. (45 to 330 min) and 106.5 min. in the last 100 patients. 30-day mortality was 0.7 % (unrelated causes) and morbidity 6.6%. The mean number of dissected nodes during TEMLA was 37.9 (15 to 85). Metastatic N2 and N3 nodes were found in 152/698 (21.8%) and 26/698 patients (3.7%), respectively. Subsequent thoracotomy was performed in 445/513 patients (86.7%) after negative result of TEMLA. During thoracotomy, omitted N2 was found in 7/445 (1.6%) patients. Sensitivity of TEMLA in discovery of metastatic N2-3 nodes was 96.2 %, specificity was 100%, accuracy was 99,0%, Negative Predictive Value (NPV) was 98.7 % and Positive Predictive Value (PPV) was 100%. CONCLUSIONS TEMLA is a new minimally invasive surgical procedure providing unique possibility to perform very extensive, bilateral mediastinal lymphadenectomy with very high diagnostic yield in staging of NSCLC Pneumonol.