BACKGROUND: Infrequent serious complications of convex-probe endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) have been reported. The aim of this study was to assess serious complications related to convex-probe EBUS-TBNA and to determine the complication rate in a large group of subjects. METHODS: In this retrospective study, a 15-item questionnaire on features of cases with EBUS-TBNA complications was sent to experienced bronchoscopists performing convex-probe EBUS-TBNA at 3 pulmonary centers. The medical records were then reviewed by these bronchoscopists to complete the questionnaire. Hemorrhage responsive to topical treatment, temporary laryngospasm/bronchospasm, transient oxygen desaturation, and fever lasting <24 h were excluded. Only complications requiring further treatment/intervention were considered serious. The rate of serious complications was calculated from the obtained data. RESULTS: In a total of 3,123 cases within a 5-y period, EBUS-TBNA was performed for staging lung cancer in 15.8%, diagnosis in 67.5%, and diagnosis and staging in 16.3%. Of the 3,123, 11.6% had parenchymal lesions adjacent to major airways. EBUS-TBNA was performed 11,753 times (3.76/case) at 6,115 lymph node stations and lesions (1.92/station or lesion). Five serious complications were recorded (0.16%): fever lasting >24 h, infection of bronchogenic cyst, mediastinal abscess, pericarditis, and pneumomediastinitis with empyema, each in one case. Four complications occurred in cases diagnosed with benign disease by EBUS-TBNA. All complications were treated with broad-spectrum antibiotics. Four subjects were hospitalized for 21.7 +/- 20.7 d. CONCLUSIONS: Convex-probe EBUS-TBNA is a safe method in general. However, serious complications, including infections, can be encountered rarely. All precautions should be taken for complications before and during the procedure.