['High serum phosphorus and the calcium-phosphorus product concentration has been associated with increased mortality and cardiovascular events in patients with chronic kidney disease.', 'This study was designed to determine the relationship between calcium-phosphorus product concentration and the presence of coronary artery calcification in subjects with metabolic syndrome (MetS).', 'We reviewed the medical records of 2056 general subjects with a mean age of 55.1 ± 9.9 years and a glomerular filtration rate of 88.9 ± 16.2 mL/min/1.73 m(2). The enrolled subjects consisted of 384 (18.7%) subjects with MetS and 1672 (81.3%) subjects without MetS. The severity of coronary artery calcification was assessed by the coronary artery calcification score (CACS) using multi-detector computed tomography (MDCT).', 'The CACS correlated with calcium-phosphorus product concentration in subjects with MetS (r = 0.184, P < 0.01). The odds ratio of calcium-phosphorus product concentration having CACS >50 was 1.053 in subjects with MetS (P < 0.05). After adjustment for age, sex, diabetes, and dyslipidemia, calcium-phosphorus product concentrations had a positive correlation with CACS in subjects with MetS. In single regression analysis, calcium-phosphorus product concentration as independent variable was the significant predictor of CACS in subjects with MetS. Using a multivariate analysis, calcium-phosphorus product concentration remained a significant factor associated with CACS in subjects with MetS.'] Is calcium-phosphorus product concentration a risk factor of coronary artery disease in metabolic syndrome?