Mean Platelet Volume (MPV) is an indicator of the average size and activity of platelets. Larger platelets contain more dense granules and hence are more potent and thrombogenic. This suggests a relationship between the platelet function especially MPV and diabetic vascular complications thus indicating changes in MPV reflect the state of thrombogenesis. The data of MPV value in diabetics and their association with vascular complications are scarse in India. Hence based on above findings the present study was planned for clinical evaluation of the mean platelet volume in patients diagnosed with type 2 diabetes mellitus and correlation with the condition. The present study was planned in Anugrah Narayan Magadh Medical College, Gaya, Bihar From Jan 2017 to july 2017. Total 100 cases of diabetes and 50 cases of the normal patients were enrolled in the present study. In the 100 diabetes patients were divided as per the with complication and without complications. MPV and platelet counts were measured in the above subjects using an automated blood counter. The blood glucose (fasting, post-prandial) levels and HbA1c levels were also measured along with urine for microalbuminuria. The data generated from the present study concludes that MPV is increased in Diabetes mellitus (DM) and that platelets become more reactive and agreeable. The increased platelet size may be a risk factor for atherosclerosis associated with DM and its vascular complications. Hence, MPV would be a useful prognostic marker of cardio-vascular complications in Diabetes mellitus (DM).