High-level evidence to guide the optimal postoperative management of patients with completely resected non-small-cell lung cancer (NSCLC) is lacking. Large randomized controlled trials have established postoperative chemotherapy as the standard of care for patients with pathologically involved lymph nodes. Recent retrospective and non-randomized studies provide evidence of the benefit of post-operative radiation therapy (PORT) in patients with mediastinal nodal involvement (N2 stage). A large multi-institutional randomized trial of PORT in this patient population is now underway. Based on currently available data, PORT may be considered for fit patients with completely resected NSCLC with N2 nodal involvement, preferably after completion of adjuvant chemotherapy. At this point, PORT is not recommended for patients with less than N2 nodal stage. Ideally, modern three-dimensional conformal radiation technique should be used, with attention to normal organ sparing, particularly lung and heart. Appropriate image guidance tools are encouraged to individualize treatment margins, account for breathing-induced motion, and minimize irradiation of normal tissues. The target volume should include at a minimum the bronchial stump, ipsilateral hilum, and involved nodal stations, and covering adjacent mediastinal nodal stations is recommended. A total dose of 50-54 Gy in 1.8-2 Gy fractions is appropriate.