A 60-year-old male was admitted because of dyspnea and angina like chest pain. Noninvasive findings showed a mass at the posterior aspect of the left atrium. The mass was removed under cardiopulmonary bypass. An encapsulated adipose mass, which originated from the left atrium without any invasion to the pericardium, was completely excised. Histological examination showed mature adipose tissue with partial necrosis, confirming the diagnosis of lipoma. We report a rare of case of massive left atrial lipoma occupying the pericardial space.