The aim of this study was to compare mean platelet volume (MPV) in patients with type 2 diabetes mellitus (T2DM), in subjects with impaired fasting glucose (IFG), and in non-diabetic controls. A total of 201 adults with T2DM and 201 subjects with IFG from the Family Medicine out-patient clinic as well as 201 healthy controls were included in the study. We measured blood fasting glucose, complete blood count and LDL-cholesterol and compared the results between the groups enrolled. In the patients with diabetes and subjects with IFG, MPV was significantly higher (10.66 +/- 0.94 fL and 10.49 +/- 0.96 fL, respectively) as compared to the non-diabetic group (10.04 +/- 1.01 fL) (p = 0.000). Among the diabetic subjects, a positive statistical Pearson correlation was seen between MPV and HbA1c levels (r = 0.357; p = 0.000) and fasting blood glucose (FBG) levels (r = 0.306; p = 0.000). The mean MPV in patients having HbA1C < 7.5% was 10.17 +/- 0.83 fL and significantly lower than that of patients with HbA1c = 7.5% (10.80 +/- 0.92 fL) (p = 0.001). MPV could be used as a simple and cost-effective tool to monitor the progression and control of T2DM and thereby in preventing vascular events in primary health care.