Hydatid cyst, which is caused by Echinococcus larvae, is a worldwide zoonotic disease which can affect virtually any organ in the body. Although the liver and lungs are the most commonly affected, it can occur in other parts of the body. Mediastinal hydatid cysts are incredibly rare, but imaging is crucial to diagnose and determine the extent of involvement and complications. In this article, we present a case of posterior Mediastinal hydatid cyst with adjacent chest wall and spinal involvement, diagnosed through chest CT and histopathology.