Primary neoplasms of the pericardium are rarer than those originating within the myocardium or endocardium and, moreover, primary benign tumors of the pericardium are of much rare occurence. Mahaim[1945] was able to collect 84 cases of pericardial tumors, the majority of which were malignant. A case of primary benign fibromyxoma of the pericardium is presented. This tumor arouse in the right anterior aspect of the pericardium, through which the phrenic nerve was penetrated. The tumor was measured 10X6X6 cm in size and 120 gm in weight. Total excision of the mass was accomplished by antero-lateral thotacotomy incision, resulting complete cure. This is the first case of primary benign fibromyxoma of the pericardium on literatures in our knowledge.[KTCS 1968;1:69-74]