Dabrafenib plus trametinib is active against metastatic lung cancer with the BRAF V600E mutation. However, the feasibility of dabrafenib plus trametinib for patients with a poor performance status (PS) has not been reported. We report the case of an 80-year-old woman was diagnosed with metastatic large-cell lung carcinoma. Her general statuses worsened due to cancer, resulting in a PS of 4. Genotype testing revealed a BRAF V600E mutation. The patient received dabrafenib plus trametinib without significant adverse effects. This report is the first to describe dabrafenib plus trametinib administration for large-cell lung carcinoma in a patient with a poor PS.