OBJECTIVES: To disseminate transesophageal ultrasound-guided fine needle aspiration (EUS-FNA) as an alternative to investigate mediastinal tumoral lesions because it is an underused modality that has been available in Brazil for more than 15 years. METHODS: Descriptive analysis of a single endoscopy service's experience since 1997 in the accomplishment of EUSFNA for mediastinal staging of previously known malignancies (Group 1) or diagnostic definition of suspect lymph nodes and masses (Group 2). RESULTS: EUS-FNA was performed in 51 patients between 26 and 87 years of age. The diameter of the lesions ranged between 1.1 and 9.8 cm (mean 3.9 cm). Their location corresponded to the following stations: higher paratracheal (4 cases), lower paratracheal (7), aortic window (12), para-aortic (6), subcarinal (9), paraesophageal (8), and hilar (5). In Group 1, 17 patients had previously diagnosed primary lung (9), breast (4), kidney (2), colon (1), and bladder (1) cancer. Fifteen of these punctures were positive for malignity. Two others were later submitted to mediastinoscopy, which identified metastases not detected by EUS-FNA. Group 2 comprised 34 patients. Among these patients, EUS-FNA diagnosed 22 neoplasms, five cases of tuberculosis and two duplication cysts. Cytology was inconclusive or without a specific diagnosis in five other cases. Mediastinoscopy identified two undiagnosed cases of oat-cell carcinoma, one lymphoma and one cryptococcosis, and confirmed one reactive lymphadenitis. There were no complications related to the method. CONCLUSIONS: EUS-FNA obviated the need for surgical procedures in 86.3% of cases. Therefore, oncologists, pulmonologists, and thoracic surgeons should always remember the technique's potential and availability.