Non-small cell lung cancer was metastasized at the septal side of right atrium in 59-year-old woman who had undergone surgery for lung cancer 11 years ago. The cardiac metastasis was found by whole-body 18F-fluoro-deoxy-glucose positron emission tomography/computed tomography (FDG-PET/CT), and cytologically confirmed by myocardial aspiration biopsy with right heart catheterization. The patient was treated with 4 cycles of carboplatin/pemetrexed followed by maintenance therapy with pemetrexed. The metastatic cardiac tumor shrank, and the atrioventricular (AV) block in ECG was improved. In this case, FDG-PET and chemotherapy were valuable for diagnosis and treatment of cardiac metastasis from non-small cell lung cancer.