Background/aim: Activation and size of platelets have been suggested to be involved in the pathogenesis of vascular complications in diabetes mellitus. The purpose of the present study was to investigate the association of mean platelet volume with microalbuminuria in type 2 diabetic patients. Materials and methods: Mean platelet volume levels were investigated in healthy participants and type 2 diabetic patients with and without microalbuminuria. After their mean platelet volume values were compared, correlation of mean platelet volume with sex, duration of diabetes, microalbuminuria, fasting blood glucose, hemoglobin A1c, creatinine clearance, and body mass index was examined. Results: Mean platelet volume levels were higher in all diabetic patients than those in controls. Mean platelet volume levels were highest in diabetics with microalbuminuria. The mean platelet volume levels had a positive correlation with microalbuminuria. Conclusion: Mean platelet volume values of diabetic patients were higher than those of nondiabetics, the highest levels being in diabetics with microalbuminuria. Our results suggest that microalbuminuria might be related with mean platelet volume in diabetic patients.