Extended resections for advanced-stage thymomas are not commonly performed because of the potential morbidity in the face of unclear survival or palliative benefit. We reviewed our experience with multimodality treatment for Masaoka stage IVA thymomas for feasibility and outcomes. We conducted a retrospective review of a single-institution surgical database. Data included patient demographics, preoperative staging and treatment, perioperative events, pathologic findings, and postoperative outcomes. During the period from 1996 to 2006, 18 patients who had Masaoka stage IVA thymoma underwent surgical resection. All patients received preoperative chemotherapy. Four patients with extensive pleural involvement underwent concomitant extrapleural pneumonectomy and postoperative hemithoracic radiation. Complete resection was achieved in 12 (67%) patients. There was no operative mortality. With a median follow-up of 32.2 months (range 1.4-129.9 months), 3-year, 5-year, and 10-year survivals were 91%, 78%, and 65%, respectively, and median survival has not yet been reached. Multimodality therapy including extended surgical resection can be performed in select patients with stage IVA thymoma with low morbidity and mortality and can result in excellent long-term survival.