A 69-year-old man with a smoking history and complaints of back pain and cough for 2 weeks was found to have a right lung mass on chest radiography results. A chest computed tomography (CT) scan showed a right upper lobe lung mass with multiple lymphadenopathies (N3), and bone scan and brain magnetic resonance imaging results showed multiple metastatic foci. A biopsy was performed, and the pathologic report showed a poorly differentiated lung adenocarcinoma with ROS1 rearrangement identified by immunohistochemical staining (clone: D4D6; H-score: 280) and further confirmative fluorescence in situ hybridization. The patient received ceritinib, 450 mg/day, and his tumor and brain and bone metastatic lesions subsequently decreased in size. The ceritinib was then shifted to crizotinib, 500 mg/day, when the reimbursement of crizotinib as a first-line therapy was approved by Taiwan's National Health Insurance system.