Lung cancer is the most common cause of cancer-related mortality in North America with non-small cell lung cancer representing the majority of cases. Despite advances in treatment, the prognosis remains poor with recurrence rates as high as 50% after surgical resection alone. In this article, we review the rationale and evidence for neoadjuvant and adjuvant therapy with chemotherapy, radiation therapy, and combined modality therapy in patients with resected non-small cell lung cancer.