Objective To discuss the diagnosis, surgical treatment, and prognosis of primary malignant cardiac tumors. Methods and Results The clinical data of 13 patients with primary malignant cardiac tumors, who were surgically treated from January,1999 to May, 2012, were retrospectively analyzed. The 13 patients accounted for 9.22% (13/141) of patients with cardiac tumors who were surgically treated during the corresponding period. The diagnoses of the 13 cases were all comfirmed by echocardiography. Median sternotomy was performed in 12 cases and left anterolateral thoracotomy in 1. Complete resection of tumor was performed in 8 cases, subtotal resection in 1, and only biopsy in 4. The tumors arose from the right atrium in 3 cases, right ventricle in 3, left atrium in 4, left ventricle in 1, and right atrium combined with right ventricle in 2 cases. Pathological diagnoses included angiosarcoma in 3 cases, rhabdomyosarcoma in 3, mesenchymal sarcoma in 3, leiomyosarcoma in 2, undifferentiated sarcoma in 1, and fibromyxoid sarcoma in 1. There was no operative or in-hospital death, and all the patients were followed up after surgery. The median survival time of the entire group was 17.5 months (range, 1-76 months). The median survival time of the patients who underwent a complete or subtotal surgical excision was 18.5 months compared with 8 months for those who underwent only biopsy. Conclusion Malignant primary cardiac tumors are often found in the right heart. Echocardiography is the most important diagnostic method. The prognosis of malignant primary cardiac tumors is very poor. Surgical excision remains an effective method to improve the prognosis.