In this paper, we demonstrate how to enhance performances of Organic Thin-Film Transistors (OTFTs) made on flexible substrates by low-cost inkjet printing technique. Especially, we focus our attention on contact resistance to the channel in order to explain the differences in OTFT performances. For this, we first evaluate, on oxidized silicon wafer, the performances of several inkjetted couples of Organic Semiconductor(OSC)/Source and Drain (SD) electrodes compared to devices with evaporated metal SD. By this way, we show that inkjet printing is a suitable low-cost technique to dispense polymers and inorganic nanoparticules for the direct-writing of OTFTs. We obtain lower contact resistances when conducting polymer (PedotlPss) contacts the OTFT channel than evaporated metal (Au, Pt). Then, our strategy consists of printing the optimized OSC/SD electrodes couples on a multilayered cheap flexible substrate, coating with an ultrathin gate oxide (4nm), which allows low-operating for the printed OTFTs ([V] <3V). All these results pave the way towards flexible electronics applications. Copyright © 2007 Materials Research Society.