An increment of abdominal visceral fat accumulation has been reported to be a coronary risk factor. We determined the predictive power of pericardial fat (Pfat) accumulation as intra-thoracic visceral fat, in the diagnosis of coronary artery disease (CAD). Among 251 (181 non-obese [body mass index<25], 70 obese [body mass index> or =25]) Japanese male patients who underwent computed tomography (CT), 128 (90 non-obese, 38 obese) patients were suffering from CAD. Pfat volume was determined by the sum of cross-sectional images 1cm thick from the atrial appendage to the apex over the diaphragm. Abdominal visceral fat (Vfat) and subcutaneous fat (Sfat) areas were measured by a single scan at the L4-L5 region. Pfat was most associated with Vfat in body fat distribution. In non-obese patients, Pfat was most associated with CAD among the various risk factors including body fat distribution. Moreover, Pfat was the strongest independent variable for the severity of CAD, determined by coronary angiogram. This result showed that pericardial fat accumulation was a stronger coronary risk factor than the other body fat distributions in non-obese men.