A 21-year-old man had a 3-year occupational history of welding. He underwent occupational medical examinations once a year and showed no abnormal findings on the chest X-ray in June 2015. He consulted a local doctor for a persistent cough since late April 2016. His chest computed tomography (CT) scan revealed small centrilobular nodules, thickening interlobular septa, and mediastinal lymphadenopathy. He underwent bronchoscopy (bronchoalveolar lavage, transbronchial lung biopsy) in a general hospital, but received no diagnois. Video-assisted thoracic surgery was performed in our hospital, and he was diagnosed with welder's pneumoconiosis based on the histopathological findings. His clinical symptoms, lung functions, and chest X-rays, as well as his liver damage, improved with no treatment. Although we did not see his liver biopsy, we speculated that the cause of liver damage might be excess iron deposition in the liver. Usually a welder's pneumoconiosis develops after 10 to 30 years of occupational exposure. We report a rare case of liver damage with an exposure history as short as 3 years.