Malignant melanoma is unique in its propensity to metastasize to the heart with frequencies ranging from 50% to 71%. We report a case of a resection of large intracavitary malignant melanoma causing obstruction of the right ventricular inflow and outflow tract of the heart. A 49-year-old-woman presented clinical symptoms and signs of life-threatening congestive right heart failure. Transthoracic and transesophageal echocardiography revealed a large intracavitary mass occupying the entire right ventricle. Inguinal lymph node biopsy demonstrated metastatic melanoma. The cardiac main mass was palliatively resected and demonstrated to be a metastatic melanoma. The patient improved symptomatically about 60 days after the operation.