Cavernous hemangioma is an uncommon benign tumor, with rare cardiac involvement. We encountered a patient with dyspnea in whom a cavernous hemangioma was located in the myocardium of the left atrium, and in whom preoperative CT demonstrated a well-demarcated mass attached to the left atrium. During the arterial phase, speckled enhancing foci were seen, and delayed-phase CT images depicted dense peripheral enhancement, similar to that of adjacent vessels. Mass resection of the tumor resulted in a satisfactory clinical course during the two-year follow-up period. We report this case, describing its preoperative CT findings.