We report here on an uncommon case of mediastinitis that occurred after central venous catheterization. A patient with colon and jejunal cancer complained high fever, right shoulder pain, chest pain, and limited motion of the affected shoulder just 6 days after central venous catheterization. Bacterial culture of the blood, shoulder abscess, and catheter puncture site revealed methicillin-resistent staphylococcus aureus. Right upper mediastinal widening on chest film also suggested mediatinitis. Mediastiotomy and pus drainage was performed along with adequate antibiotics therapy. In this case, it seems that initially formed bacteria from the puncture site migrated to the mediastinum through the tissue plane to start the mediastinitis. Careful dressing of puncture site and correct handling of catheter is important to prevent this serious complication.