Aim: To investigate the mean thrombocyte volume (MPV) in asymptomatic children infected with COVID-19. Methods: The study included 55 children infected with COVID-19 and 60 healthy children for the comparison of leukocyte and thrombocyte count, MPV, and serum C-reactive protein (CRP) levels. Demographic data and clinical findings of all the cases were recorded, including age, gender, weight, temperature, cough, shortness of breath and contact history. Results: The MPV values were determined to be statistically significantly high (p<0.001) and the lymphocyte values were significantly low (p:0.002) in the asymptomatic children infected with COVID-19 compared to the healthy control children. No difference was determined between the groups in respect of CRP level, leukocyte and thrombocyte counts (p>0.05). The optimal cutoff point for MPV was determined as 8.74 fl (Area under the curve-AUC:0.932) with 81.82% sensitivity and 95% specificity for the determination of children infected with COVID-19. A cutoff value of <2.12/mm3 for lymphocytes (AUC:0.670) was determined with 49.09% sensitivity and 86.67% specificity for the prediction of COVID-19. Based on the ROC analysis, the sensitivity and specificity of MPV was determined to be higher than that of lymphocyte levels. Conclusion: The results of this study that MPV levels are significantly high in asymptomatic children infected with COVID-19 demonstrate that this is an important predictive value and has better predictive capacity than lymphocyte values. The evaluation of MPV and lymphocyte levels together could increase diagnostic success in asymptomatic COVID-19 cases.