Background: The phase 3 ICOGEN trial established the non-inferiority of icotinib to gefitinib in terms of progression-free survival (PFS) in non-small cell lung cancer (NSCLC) patients, and this led to the approval of icotinib for NSCLC by the China Food and Drug Administration. A phase 4 study was conducted to assess the safety and efficacy of icotinib in a broad range of patients with advanced NSCLC across China. Methods: This study retrospectively analyzed data from unresectable, recurrent, and/or advanced NSCLC patients who received oral icotinib 125 mg three times per day. The primary endpoint was safety. The secondary endpoints included objective response rate (ORR) and disease control rate (DCR), which were investigated overall and in subgroups such as patients with an EGFR mutation and elderly patients. Results: Between August, 2011 and August, 2012, a total of 6087 advanced NSCLC patients were registered in this study, of which 5549 were evaluable for safety and tumor response. The median age was 63 years (range 21-95 years), and 1571 (28.3%) patients were over the age of 70. The majority of patients were non-smokers, and had adenocarcinoma and stage IV disease. The overall incidence of adverse drug reactions (ADRs) of any grade was 31.5%. The most common ADRs included rash (17.4%) and diarrhea (8.5%), and three patients experienced interstitial lung disease (ILD). The ORR and DCR were 30.0% and 80.6%, respectively, for the overall population, and 33.4% and 81.2%, 30.3% and 80.3%, and 30.4% and 89.3%, for first-line, second-line, and third-line or multiple line subsets, respectively. In 665 EGFR-mutated patients who were evaluable for tumor response, the ORR and DCR were 49.2% (327/665) and 92.3% (614/665), respectively. Conclusions: The data from over 6000 patients was consistent with the results of the ICOGEN study. Icotinib demonstrated a favorable toxicity profile and efficacy in the routine clinical setting. (C) 2014 Elsevier Ireland Ltd. All rights reserved.