We report a case of a female in her 80s who was diagnosed with recurrent lung adenocarcinoma after primary surgery. She was treated with a systemic chemotherapy regimen consisting of carboplatin plus paclitaxel until the disease showed progression. On detection of epidermal growth factor receptor(EGFR)mutations, we administered gefitinib, an EGFR tyrosine kinase inhibitor, at a dosage of 250 mg daily. After 6 months of gefitinib therapy, laboratory findings revealed elevated serum aspartate aminotransferase(AST)and alanine aminotransferase(ALT)levels(grade 2), indicative of hepatotoxicity. Gefitinib was discontinued and erlotinib was initiated at a dosage of 50 mg daily. She continued the therapy for 3 years, during which her disease stabilized without any further complications or hepatotoxicity. Thus, low-dose erlotinib may be effective and well tolerated by patients with non-small cell lung cancer harboring EGFR mutations who are intolerant to gefitinib.