Lung cancer has a high mortality rate and is often diagnosed in locally advanced or metastatic stages. A new therapeutic option for patients with non-small cell lung cancer (NSCLC) in these stages with progress or relapse after platinum-based chemotherapy exists in the inhibitors of the epidermal growth factor receptor (EGFR) tyrosine-kinase. EGFR tyrosine-kinase inhibitor treatment might also be an option for patients ineligible for surgery and conventional chemotherapy. We present a case of a 53-year-old woman who was diagnosed due to pain from multiple bone metastases of a lung adenocarcinoma. She refused cytotoxic chemotherapy, and we administered first-line systemic treatment with gefitinib subsequent to radiotherapy of metastatic bone disease. The patient responded well to gefitinib treatment and achieved a partial response after 3 weeks. No relevant side effects occurred, and the patient experienced an 8-month remission of disease. With a follow-up of 10 months, the patient is still alive. Retrospectively, we found a mutation of the EGF receptor in tumor cells of the patient, which is associated with sensitivity to gefitinib. EGFR tyrosine-kinase inhibitors (TKI) can be an alternative first-line systemic treatment option for selected patients with metastatic NSCLC.