Background. Mediastinoscopy and endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNA) are complementary for staging non-small cell lung cancer (NSCLC) patients. We assessed (1) the yield of EUS-FNA of malignant lymph nodes in NSCLC patients with combined anterior and posterior lymph nodes that had already undergone mediastinoscopy and (2) the cost implications associated with alternative initial strategies. Methods. All patients underwent chest computed tomography (CT) and/or positron emission tomography (PET), and mediastinoscopy. Then, the posterior mediastinal stations (7, 8, and 9) or station 5 were targeted with EUS-FNA. The reference standard included thoracotomy with complete thoracic lymphadenectomy, repeat clinical imaging, or long-term clinical follow-up. A Monte Carlo cost-analysis model evaluated the expected costs and outcomes associated with staging of NSCLC. Results. Thirty-five NSCLC patients met inclusion criteria (median age 65 years; 80% men). Endoscopic ultrasound-guided FNA was performed in 53 lymph nodes in various stations, the subcarinal station (7) being the most common (47.3%). Of the 35 patients who had a prior negative mediastinoscopy, 13 patients (37.1%) had malignant N2 or N3 lymph nodes. Accuracy of EUS-FNA (98.1%) was significantly higher than that of CT (41.5%; p < 0.001) and PET (40%; p < 0.001). Initial EUS-FNA resulted in average costs per patient of $1,867 (SD ± $4,308) while initial mediastinoscopy cost $12,900 (SD ± $4164.40). If initial EUS-FNA is utilized rather than initial mediastinoscopy, an average cost saving of $11,033 per patient would result. Conclusions. In patients with NSCLC and combined anterior and posterior lymph nodes, starting with EUS-FNA would preclude mediastinoscopy in more than one third of the patients. Endoscopic ultrasound-guided FNA is a safe outpatient procedure that is less invasive and less costly than mediastinoscopy. © 2005 by The Society of Thoracic Surgeons.