Thyroid cancer is the most frequent cancer of the endocrine glands and the fifth most frequent cancer in women. Activated platelets play a crucial role in thrombosis, inflammation, and cancer. Mean platelet volume (MPV) and platelet distribution width (PDW) are early index of platelet activation. The purpose of this study is to investigate platelet indices levels in thyroid cancer. The study enrolled 280 patients with thyroid cancer and 280 control subjects. Patients' characteristics and hematologic tests data were collected at the time of diagnosis. Correlations between platelet indices and clinical characteristics were analyzed. The odds ratios (ORs) and 95% confidence intervals (CIs) for thyroid cancer were calculated using multivariate logistic regression analyses across MPV and PDW quartiles. The patients with thyroid cancer had lower MPV and higher PDW compared with control subjects. MPV was correlated with tumor-nodus-metastases (TNM) stage and lymph node metastasis. Moreover, after adjusting for other risk factors, the prevalence risk of thyroid cancer for the lowest quartile of MPV was 7.242 (4.069-12.887) (P < 0.001) and for the highest quartile of PDW was 6.065 (3.321-11.076) (P < 0.001), respectively. The study showed that the patients with thyroid cancer have lower MPV and higher PDW compared to control subjects. Moreover, MPV and PDW were independently associated with the presence of thyroid cancer. Further studies are needed to evaluate the utility of MPV and PDW as novel diagnostic screening tools for thyroid cancer.