Platelet (PLT) indices mean platelet volume (MPV), platelet hematocrit (PCT) and platelet distribution width (PDW) are probably the most ignored parameters by the clinicians. Although several studies held among different disease states, they do not have diagnostic value yet. Our aim was to determine the reference range of platelet parameters in venous blood samples of a population with an age range 6 months to 18 years in a hospital laboratory. This retrospective study consisted of 710 healthy children and the subjects were categorized into five groups according to their age. Age distribution of these groups was 6 months; 12 months; 18 months; 2-5 years and 6-18 years respectively. Our data revealed significant differences with regard to the MPV, PCT and PDW among the groups (p<0.001). Also, it was found that the increased PLT count was statistically associated with an elevated PCT value (r = 0.91, p < 0.0001) and the number of PLT correlated negatively with MPV (r = -0.38, p < 0.001). PDW showed a positive correlation with MPV (r = 0.3, p < 0.001), but negatively with PLT (r= -0.2) and PCT (r = -0.1) (p < 0.001). Our data revealed that determination of the PDW reference range is fundamental, and the association of this parameter with the platelet number and mean platelet volume may be used for the diagnosis and differentiation of several pathologies.