Background Erlotinib is an oral, epidermal growth factor receptor tyrosine kinase inhibitor that has antitumor activity and good tolerability in non–small-cell lung cancer (NSCLC). In particular, higher response rates have been noted in Asian patients than Western patients. The aim of this study (EAP [Expanded Access Program]) is to evaluate the efficacy and tolerability of erlotinib alone as a palliative treatment for patients with advanced NSCLC in Korea. Patients and Methods Patients with histologically or cytologically confirmed stage IIIB/IV NSCLC including recurrent or metastatic disease with a performance status (PS) of 0-3 were eligible if they had received any anticancer treatment except epidermal growth factor receptor inhibitors, if they had never been treated, or if they had poor PS. Enrolled patients were treated with oral erlotinib 150 mg daily until disease progression or development of intolerable toxicity. Results The median age of the 120 patients was 61 years, and 63.3% were men; 89.1% had PS of 0/1; 50.8% had received 1 previous palliative chemotherapy regimen, and 33.3% had ≥ 2 previous palliative regimens. Overall tumor response rate, including complete and partial response, was 23.3%, and an additional 18.3% of patients exhibited stable disease. Superior tumor responses were observed in women (P = 0.001), never-smokers (P = 0.047), and those with histology of adenocarcinoma (P Conclusion Erlotinib alone showed clinically significant antitumor activity and an acceptable tolerability profile as a palliative treatment in patients with advanced NSCLC in Korea, especially in women, never-smokers, patients with adenocarcinoma histology, and in cases with rash.