BACKGROUND: Platelet has been known as an implicating factor in the pathophysiology of atherosclerotic disease. Larger platelets are more reactive and produce more prothrombotic factors. Several studies have shown relationship between mean platelet volume (MPV) and coronary artery disease. The present study has been designed to investigate association of MPV and subclinical CAD (coronary artery disease; abnormal finding in coronary multidetector computed tomography [MDCT] in asymptomatic individual). METHODS: This cross sectional study was carried out in 103 men and 72 women (over 40 years old) who underwent coronary MDCT as screening test for disease prevention in the health examination center of Hanyang University Medical Center in Korea from January 1 to April 30, 2009. Subclinical CAD was defined when either of the following findings are present in asymptomatic patients: 1) plaque or calcification, 2) stenosis of any level. After adjustment for age, gender, hypertension, diabetes, BMI, smoking (pack-years), LDL cholesterol, odds ratios (ORs) for the prevalence of the subclinical CAD were calculated for quintiles of MPV using logistic regression analysis. RESULTS: After adjustment for age, gender, hypertension, diabetes, BMI, smoking (pack-years), LDL cholesterol, the OR for subclinical CAD, comparing the fifth quintile of MPV with the first quintile, was 5.83 (95% confidence interval, 1.51 to 22.42; P = 0.010). CONCLUSION: Highest level of MPV is independently associated with the prevalence of the subclinical CAD after adjusting for other risk factors.