This study was conducted to compare mean platelet volume (MPV) in ankylosing spondylitis (AS) patients with that of healty controls, analyze the effect of disease status and presence of traditional cardiovascular risk factors (CRF) such as smoking, hypertension, hyperlipidemia, diabetes and obesity. Retrospectively, 152 patients with AS were included. The control group included 55 sex- and age-matched healty subjects without any risk factors and concomitant diseases. MPV level in AS patients was higher than healthy controls, MPV and PLT levels in AS patients with at least on one traditional CRF were not significantly different compared to patients without any risk factor. MPV showed no significant association with any disease activity. There was no significant difference between active and inactive state in AS patients according to MPV. Patients have higher MPV than healthy controls indicating higher risk of cardiovascular involvement and atherosclerosis. AS alone may be responsible of this increment instead of traditional CRF's.