Patients with confirmed stage IIIA non-small cell lung cancer (NSCLC) represent a very heterogeneous group which includes those with limited microscopic ipsilateral mediastinal lymph node involvement discovered after a surgical resection, as well as those who have radiologically evident bulky subcarinal lymph node involvement at presentation. Different therapeutic options in stage IIIA disease include neoadjuvant chemo- or chemoradiotherapy followed by surgery, primary surgery followed by adjuvant chemotherapy with or without sequential adjuvant radiation therapy or definitive chemoradiation without surgery. The roles of surgery and radiation in stage IIIA disease are controversial, and there is inadequate data from randomized trials to inform the optimal therapeutic strategy. In contrast, chemotherapy has a clear indication in the curative setting. Data from randomized trials indicates that cisplatin-based chemotherapy should be given in either adjuvant or neoadjuvant settings to patients who are undergoing curative surgical resection and who are candidates for cisplatin therapy. In definitive chemoradiotherapy, cisplatin-based therapy is recommended although a carboplatin-based regimen may be given if patients cannot receive cisplatin. Finally, all patients with stage IIIA NSCLC should be evaluated early in a multidisciplinary setting that includes medical and radiation oncologists and thoracic surgeons with experience in lung cancer therapy.