Patients with stage IIIA non-small cell lung cancer, determined based on involvement of ipsilateral mediastinal lymph nodes, represent the most challenging management problem in this disease. Patients with this stage disease may have very different degrees of lymph node involvement. The pathologic confirmation of this involvement is a key step in the therapeutic decision. The difference in the degree of lymph node compromise has prognostic and treatment implications. Based on multiple considerations, patients can be treated with induction chemotherapy, chemoradiotherapy followed by surgery, or definitive chemoradiotherapy without surgery. Data derived from clinical trials have provided incomplete guidance for physicians and their patients. The best therapeutic plan is achieved through the multidisciplinary cooperation of a team specialized in lung cancer.