Transesophageal echocardiography (TEE) was performed on a 41-year-old woman who presented with a cerebrovascular accident. TEE confirmed the presence of a morphologically bizarre biatrial tumor with precarious, vigorous motion throughout the cardiac cycle. Surgical intervention was decided on, and the patient underwent cardiac surgery for tumor excision 16 hours after TEE. Intraoperative frozen section diagnosis was spindle cell sarcoma, and subsequent immunohistochemical analysis showed the tumor to be a rhabdomyosarcoma. The data are presented here, and the role of TEE to establish a preoperative diagnosis of intracardiac tumor is discussed.