Objectives: Surgical resection is standard treatment for early-stage non-small cell lung cancer; however, perception of postoperative risk may influence the decision to proceed for elderly patients. With population data, we analyzed postoperative complications and morbidity predictors for older patients undergoing lobectomy for stage I non-small cell lung cancer. Methods: The Surveillance Epidemiology and End-Results-Medicare linked database (2000-2005) identified patients (ages 66-80 years) undergoing lobectomy for stage I non-small cell lung cancer. We comprehensively evaluated in-hospital postoperative complications (pulmonary, cardiac, infectious, noncardiopulmonary) with International Classification of Diseases, Ninth Revision, diagnosis codes. Logistic regression models were constructed to identify patient, tumor, and treatment characteristics associated with complications. Results: In all, 4171 patients were included, 2329 of whom had 4097 in-hospital postoperative complications (55.8%). Pulmonary complications were most common (n = 1598; 38.3%) followed by cardiac (n = 1020; 24.5%). Complications were significantly associated with age at least 75 years, male sex, higher comorbidity index, larger tumors, and treatment at nonteaching hospitals (P < .05). Patients with complications had a longer median stay (8 days) than patients without (6 days; P < .001). The 30-day mortality was 4.2%. Conclusions: Population-based analysis demonstrated that perioperative complications after lobectomy for stage I non-small cell lung cancer in older patients exceeded 50% and were associated with specific patient, tumor, and treatment characteristics. Better understanding of the impact of these risk factors may facilitate surgical decision making and encourage implementation of more effective perioperative care guidelines for older surgical patients.