Pericardial cysts classically are found in the right or left cardiophrenic angle and rarely are located outside of this location. An 82-year-old man presented with an asymptomatic cystic mass on chest CT-scan located in the upper right mediastinum and measuring 7 x 6 x 4 cm. A follow-up chest CT-scan 12 months later showed that the cyst had increased in size to where it now measured 10 x 9 x 8 cm and was noted to be dislocating and compressing the superior vena cava. The patient underwent surgical excision because of the uncertain diagnosis and the compression of contiguous organs. Two cystic masses were able to be completely excised intact. A definitive diagnosis of double pericardial cyst was histopathologically confirmed. Radiological findings of a pericardial cyst in the upper mediastinum are extremely rare. In particular there have been no reports of bilocular or double pericardial cysts.