Malignant primary cardiac tumors are rare, with atrial myxoma and rhabdomyosarcoma the common types in adult and pediatric populations respectively. Rhabdomyosarcomas are rare and are usually located in the atria; they present with symptomatology dependent on their location. A 63-year-old woman presented with the symptomatology of dyspnea, cough, and palpitations and was diagnosed with biatrial primary cardiac rhabdomyosarcoma, which required excision. The postoperative course was uneventful and the patient was discharged on the 5th postoperative day. Postoperative cardiac functional tests revealed an ejection fraction of 60%, consistent with the preoperative value, and no mitral valve dysfunction. Biatrial rhabdomyosarcomas are extremely rare, with only 3 cases reported, including ours, reported in the literature, to the best of our knowledge. Transthoracic echocardiogram is useful in the diagnosis. They require surgical excision along with chemotherapy or radiotherapy. Their prognosis is poor, with a median survival of almost one year. Primary biatrial rhabdomyosarcoma is an extremely rare diagnosis that can present with symptomatology based on the location, size, and number of masses. There is no consensus on how to manage them due to the scarcity of cases, but they are managed as single rhabdomyosarcomas. The majority require surgical excision, with subsequent chemotherapy or radiotherapy. The prognosis is very poor, with the majority of the patients not surviving longer than one year.