Not only inflammatory diseases with a high inflammatory burden, but also neoplastic disorders have been associated with MPV. An increase in MPV has been described in various inflammatory conditions ( 7- 9). Activation of platelets is associated with an increase in MPV value ( 6). It is an index of routine hemogram tests and reflects platelet size. One of these markers is the hemogram derived mean platelet volume (MPV). Association between neoplasm and many inflammatory markers has been studied recently ( 5). Inflammation has a crucial role in the development of cancer ( 3, 4). Ultrasound scan and scintigraphy features help discriminate these nodules, especially in cases with a history of exposure to radiation. Since an important proportion of thyroid nodules include malignant cells, clinicians should search for possible malignancy, especially in suspected nodules. The prevalence of thyroid nodules on ultrasound may be as high as 67% ( 2). Advances in imaging modalities such as ultrasound scan have increased the rate of nodule detection in the gland. Women are more likely to develop thyroid nodules, and in iodine deficient countries, its prevalence may reach 5% ( 1). Physicians and surgeons pay much attention to evaluating thyroid nodules due to the malignant potential of these growths. However, further prospective studies are required to confirm its usefulness in this population. Increased MPV should be considered as an assistive diagnostic tool in differentiating malignant and benign thyroid nodules. The difference was statistically significant (p<0.001). MPV was higher in the malignant thyroid nodule group than in the benign nodule group (9.1☑ fL vs. We retrospectively analyzed hemograms of patients having undergone thyroid surgery for thyroid nodule between January 2013 and January 2015, and compared them to those recorded in healthy subjects. Since some of thyroid nodules are malignant, we aimed to compare MPV values between patients with malignant and benign thyroid nodules after precise pathologic diagnosis. Increase in the mean platelet volume (MPV) has been described in various inflammatory conditions. Inflammation has a crucial role in the development of cancer.