Objective: Crimean-Congo hemorrhagic fever (CCHF) is a life-threatening viral zoonotic disease with hemorrhagic symptoms. The aim of this study was to evaluate the effect of platelet volume and mass related indexes such as platelet count (PLT) and mean platelet volume (MPV) and mean platelet mass (MPM) on disease severity score in CCHF cases. Material and Methods: Data from 22 patients admitted to the pediatric intensive care unit between 1 December 2013 – 15 August 2016, were retrospectively examined. Age, gender, biochemical and microbiological data, platelet count, MPV and MPM, hemorrhagic symptoms and mortality status were recorded. Results: statistically, an increase in MPV and a significant decrease in PLT and a significantly higher activated partial thromboplastin time (aPTT) were observed in patients with severe CCHF compared to the group with mild CCHF according to the disease symptom scoring index grouping. No significant difference was found between mild and severe CCHF groups in terms of MPM. Conclusion: This is the first study to evaluate platelet functions in CCHF in patients admitted to the pediatric intensive care unit. Platelet functions can contribute to classification according to the symptom scoring index of patients as well as PLT. This study suggests that MPV values in the admission may be useful in predicting disease severity.