The radiological studies are very important in the diagnosis of pericarditis. The clinical and radiogicalfindings of 57 cases of pericarditis which were diagnosed at the Seoul National University Hospital during pastseven years from January 1969 to November 1976 are analysed. The diagnosis was based on aspiration of thepericardial fluid with or without air replacement, operation such as pericardiotomy or pericardiectomy and otherclinical studies. Performed radiological studies include simple chest PA and lateral, fluoroscopy,pneumo-pericardiography, cardiac scan, echocardiography and angiocardiography. The results are as follows ; 1.There is no sex difference of incidence and age distribution is even in all age groups. 2, The tuberculous originis most common and 42.1% of total 57 cases, and pyogenic, malignant, cardiomyopathy, uremia and trauma are theetiology in decreasing order. The idiopathic pericarditis are 11 cases. 3. Te main symptoms were dyspnea(61.4%),chest pain(14.0%), abdominal distension(14.0%) and the physical findings of pericarditis were remote heartsound(59.6%), hepatomegaly(59.6%) and neck vei engorgement(49.1%) 4. Pericardiocentesis was performed in 37 casesand the nature of the effusion was bloody in 51.4%, seroexudate in 29.7% and pus in 18.9%. 5. Cardinal findings ofpericardial effusion in simple chest PA were cardiomegaly (80.7%), acute cardiophrenic angles (68.4%), pleuraleffusion(56.1%) and straightening of left cardiac border or narrowing of cardiac waist (49.1%) 6. On thepneumopericardiography, the thickness of the pericardium is not related to the etiology but to the duration of thedisease.