Percutaneous computed tomographic (CT) fluoroscopy–guided biopsy was performed to evaluate an intracardiac tumor located within the left atrium of a 72-year-old woman. Postinterventional follow-up was unproblematic and free of complications. Histopathologic examination revealed a high-grade cardiac sarcoma, and the patient underwent consecutive resection and radiation therapy. In general, percutaneous puncture of the heart must be considered hazardous. Under certain conditions (eg, broad-based tumor, advanced luminal mass, myocardial and/or pericardial infiltration), however, percutaneous CT-guided biopsy may be an appropriate alternative to transluminal catheter biopsy for the minimally invasive investigation of cardiac tumors.