The Eastern Cooperative Oncology Group conducts phase II and III trials for the treatment of resectable and unresectable stage III non-small cell lung cancer, and also participates in a number of Intergroup studies. For resectable disease, the Eastern Cooperative Oncology Group is participating in a phase III prospective randomized, double-blind, placebo-controlled trial of the epidermal growth factor receptor antagonist gefitinib (ZD1839), a phase II trial for superior sulcus tumors of induction chemoradiotherapy with cisplatin/etoposide followed by surgical resection, followed by docetaxel. For unresectable disease, a phase III trial of carboplatin, paclitaxel, and thoracic radiation therapy with or without thalidomide is underway. Proposed studies include a feasibility phase II study of chemotherapy/hyperfractionated accelerated radiation therapy (HART) + cetuximab (an antibody specific for epidermal growth factor receptor) and a phase II trial of pharmcogenomics-directed adjuvant chemotherapy for completely resected non-small cell lung cancer.