The autors report size dependence of characteristics of C-60 field-effect transistors (FETs). The transport properties of the channel and the contact resistance between the channel and electrodes are extracted from size dependence. Contact resistances are comparable to those of channel resistances, and the gate voltage dependence of contact resistance is greater than that of channel resistance even at linear region. Results show that the Schottky barriers between the channel and the electrodes still affect device characteristics in the on state of C-60 FETs. (c) 2006 American Institute of Physics.