Background Mediastinal lesions are often difficult to diagnose in clinical practice because of the unique anatomical position of the mediastinum,which makes performance of biopsy difficult.The value of endobronchial ultrasound-guided transbronchial needle aspiration in the diagnosis of lung cancer and mediastinal lymph node staging has been widely accepted.However,few studies have been conducted on the value of endobronchial ultrasound-guided transbronchial needle aspiration in the diagnosis and differential diagnosis of mediastinal lesions.The current study was conducted to investigate the value of endobronchial ultrasound-guided transbronchial needle aspiration in the diagnosis and differential diagnosis of isolated mediastinal lesions without lung abnormalities.Methods We retrospectively analyzed the data of patients with isolated mediastinal lesions without lung abnormalities for whom endobronchial ultrasound-guided transbronchial needle aspiration examination was performed at the Department of Thoracic Surgery of Peking University People's Hospital,between September 2009 and December 2010.For patients who could not be diagnosed with endobronchial ultrasound-guided transbronchial needle aspiration,surgical biopsy or more than 6 months of clinical and imaging follow-up was carried out.Results Endobronchial ultrasound-guided transbronchial needle aspiration was performed for 60 patients with isolated mediastinal lesions.Correct diagnosis was made in 48 cases.Nineteen cases were malignant,and 29 were benign.The rate of correct diagnosis was 80％.The sensitivity,specificity,and accuracy of endobronchial ultrasound-guided transbronchial needle aspiration in distinguishing benign from malignant mediastinal lesions were 95％,100％,and 98％,respectively.The examination was tolerable for all patients.No associated complications were observed.Conclusion Endobronchial ultrasound-guided transbronchial needle aspiration is a safe and effective method of diagnosing mediastinal lesions.