Objective Platelet activity and aggregation potential are essential components of thrombogenesis and atherosclerosis. The mean platelet volume(MPV), which is a marker of platelet size and platelet activity, can be conveniently measuring as part of whole blood count. It has been shown that MPV was significantly higher in diabetes mellitus. The aim of this study was to investigate the relationship among MPV, glycemic control and micro and macrovascular complications in type 2 DM without clinical cardiovascular disease. Methods From August 2011 to August 2012, 270 Type 2 diabetic patients (129 male, 141 female) entering the diabetes care center of Incheon St. Mary’s hospital were included in this study. Basic clinical information was required by a standardized questionnaire. Brachial-ankle PWV as a marker of stiffness of artery was measured and mean and maximal carotid IMT was evaluated by B-mode ultrasound. Platelet counts and MPV were measured using an automated blood cell counter. The fasting blood glucose levels, HbA1C and urine albumin/creatinine ratio (UACR) were also measured. Results The mean age of study population was 56.71 ± 12 years in men, 58.56 ± 10.84 years in women and the mean duration of diabetes was 7.95 ± 7.89years and 7.71 ± 7.13 years, respectively. In men, MPV was significantly correlated with fasting glucose and HbA1c (r = 0.325 and r = 0.415, respectively, P = 0.000). In women MPV was significantly correlated with HbA1c (r = 0.323, P = 0.000). Multivariable analysis identified that MPV levels were independently associated with HbA1c in men and women (P = 0.000) but not diabetic vascular complications. Conclusion Our results suggested a close relationship between poor glycemic control in type 2 DM. But, we did not find a significant correlation between MPV and diabetic micro- and macrovascular complications.