We describe our clinical experience of eight cases of secondary cardiac tumor. The pathology of the tumors were lymphoma (three), Wilms' tumor (two), malignant teratoma (one), neuroblastoma (one), and pleuropulmonary blastoma (one). Metastatic sites were the right atrium in Wilms' tumor and neuroblastoma, the left atrium in pleuropulmonary blastoma and malignant teratoma, and multiple sites in lymphoma. Primary masses in the mediastinum extended directly to the heart (three lymphoma, malignant teratoma, pleuropulmonary blastoma). Wilms' tumor and neuroblastoma showed cardiac metastases through the inferior vena cava. Many cases revealed vague abnormal cardiovascular findings (symptoms in six; physical signs in five). In five cases surgery was performed to relieve the possible obstruction to flow and to identify the pathology (lymphoma in three, Wilms' tumor in one, and malignant teratoma in one). Chemotherapy prior to operation resulted in the disappearance of the intracardiac masses in each case of Wilms' tumor and pleuropulmonary blastoma. All three patients with lymphoma died immediately after operation. Four died of multiple metastases or Pneumocystis pneumonia several months after operation. This study indicates that suspicion of a secondary cardiac tumor is crucial to early diagnosis. Because of the poor postoperative outcome, surgery for secondary cardiac tumors should be done cautiously only in cases with definite hemodynamic decompensation.