Although liver transplantation (LT) is frequently associated with thrombocytopenia, thrombopoiesis following LT remains to be evaluated. We analyzed platelet counts (PLT), immature Platelet Fraction (IPF), and thrombopoietin (TPO) in 8 patients with LT. PLT and IPF were measured using Sysmex XE-2100. TPO was measured with Human TPO ELISA Kit. In 7 of 8 patients with LT, IPF increased prior to the elevation of platelet counts. In 5 of 7 patients with increased IPF, TPO levels increased simultaneously with IPF, suggesting that IPF may reflect the production of platelets in patients with LT. IPF and TPO might be useful to monitor the platelet production in patients following LT.