BACKGROUND Elderly patients are underrepresented in trials that establish definitive chemoradiotherapy as the standard of care for inoperable stage III non-small-cell lung carcinoma (NSCLC). This study analyzed radiotherapy treatment delivery and outcomes at our institution according to elderly (≥ 70 years old) or younger (< 70 years) age. METHODS Records of patients who received radiotherapy for stage III NSCLC between January 1998 and February 2010 were reviewed. Factors analyzed included Eastern Cooperative Oncology Group Performance Status (ECOG PS), weight loss, radiation therapy intent, and chemotherapy administered. RESULTS A total of 189 patients with stage III NSCLC were analyzed (age range, 28-92 years). Elderly patients (n = 86) were more likely to have ECOG PS ≥ 2 (P < .05) and receive palliative treatment (P < .05). Elderly patients less often received concurrent chemoradiotherapy (P < .05) as well as cisplatin (P < .05). Median survival was 10.3 months for elderly patients compared with 17.2 months for younger patients (P < .05 ). In addition, elderly patients with ECOG PS (P < .05) as well as those who received definitive concurrent chemoradiotherapy (P < .05) had inferior outcomes compared with otherwise similar younger patients. However, on multivariate analysis, elderly age was not associated (P = .428) with increased risk of death, whereas poor ECOG PS (≥ 2) was significant (P < .05). In elderly patients, definitive treatment (P < .05), chemotherapy administration (P < .05), and ECOG PS of 0-1 (P < .05) were associated with improved outcome. CONCLUSIONS Although elderly patients with stage III NSCLC experience inferior outcomes than younger patients with comparable disease, they are also more likely to receive suboptimal therapy. On multivariate analysis, advanced age was not associated with worse survival, which indicates that appropriately selected elderly patients should receive definitive chemoradiotherapy.