Platelet counts, adhesiveness, aggregation and spreading capacity, as well as the thrombopoiesis index, thrombelastogram and fibrinogen were examined in 74 healthy children aged from 2 to 14 years. Sex-linked differences were only found in the thrombopoiesis index. Age-linked differences showed in practically all the parameters, especially in the platelet counts, fibrinogen and thrombelastograms.