© 2021 College of Physicians and Surgeons Pakistan. All rights reserved.Objective: The purpose of the present study was to determine the effects of exenatide treatment on platelet function in type 2 diabetes mellitus (DM) patients. Study Design: Case-control observational study. Place and Duration of Study: University of Health Sciences, Diskapi Yildirim Beyazit Training and Research Hospital, Ankara from October 2016 to October 2018. Methodology: This study included 50 patients with type 2 DM, who had started exenatide therapy; and age-gender matched 54 control subjects. The biochemical data and BMI of the patients were analysed at the time of admission and after six months of exenatide treatment. Results: PDW (platelet distribution width) and MPV (mean platelet volume) were higher in the diabetic patient group than in the control group (p <0.01 and p=0.036, respectively). Significant positive correlations were determined between PDW and BMI (p<0.001), FPG (p <0.001), and HbA1c (p<0.001). After six months of exenatide treatment, PDW (p = 0.015) values and platelet count (p = 0.003) were significantly decreased. Conclusions: Exenatide causes a decrease in PDW value and platelet count independent of its positive effect on lipid profile, glycemic regulation, and weight loss, which contributes to explain the effect of treatment on the cardiovascular system through a different mechanism.