We present chest x-ray and computed tomography (CT) findings of mediastinal and pleural gossypibomas in three cases. Radiological manifestations change according to the location and chronicity of the sponge, and type of the reaction they cause in the body. CT readily diagnosed gossypibomas in the early postoperative period by showing well defined mediastinal or pleural based masses with hyperdense rim, and central air bubbles. However, in one patient presented in the late postoperative period, CT revealed well-defined solid pleural mass devoid of air bubbles, and correct preoperative diagnosis could not be established. Radiologists should be aware of different manifestations of this rare condition in cases with prior thoracic surgery and continuing respiratory symptoms.