Mediastinal lymph node enlargement in operable non-small cell lung cancer is of clinical importance since it indicates the high possibility of nodal metastasis. The coincidence of tuberculosis and lung cancer is detected by the mediastinal lymph node staging of lung cancer patients. In our study, we retrospectively re-evaluated the records of patients who had been hospitalized with the diagnosis of lung cancer for the past 10 years. The mean age was 58 +/- 10 years (ranging from 39 to 72). A tuberculous lymphadenitis was detected in 16 of the 315 (5.1%) patients in one and/or multiple stations by either mediastinoscopy or thoracotomy. Inferior paratracheal lymph nodes (4R-4L) were the most frequently affected. None of the patients had a history of primary tuberculosis infection. The cell type was squamous cell carcinoma in ten patients (62.5%) and adenocarcinoma in six patients (37.5%). The tumour was located in the right lung in nine patients (56.2%). The most frequently involved site was the right upper lobe (n = 13, 81.2%). N2 disease was detected in six patients (37.5%). Our study showed that 5.1% of lung patients had tuberculous lymphadenitis coincidentally. The diagnosis and treatment of this latent disease could be considered as important, especially in lung cancer patients who would potentially receive radiotherapy or chemotherapy which alters the immune system. However, the real value of this finding needs further study.