Pericardial cysts are rare lesions. These benign anomalies are located in the middle mediastinum. In this article, we present a 24-year-old man who was referred to the emergency department with dyspnea and persistent cough. In physical exam, no abnormality was found. His past medical history was normal. His trans-thoracic echocardiogram showed an echo-lucent space next to the right atrium at the right cardiophrenic angle. No pericardial effusion was found. The patient underwent surgery. After midsternotomy, a huge cyst measuring approximately 13 × 8 × 5 cm in diameters was found on the right side and outside the pericardium that was totally excised. After 5 days, the patient was discharged and pathologic report confirmed preoperative diagnosis of pericardial cyst. Giant pericardial cysts are not common and in this report, we will review published case reports.