A concept for organic field effect transistors (OFETs) based on polymeric foils is presented. Starting with a short description of the basic OFET design, the selection of materials used as organic semiconductor, substrate, electrodes and gate insulator is discussed. In order to obtain reference values from well-characterised test chips, transistor measurements carried out using silicon/silicon dioxide substrates are described. The characteristic values extracted from these measurements serve as input data for the simulation of a ring oscillator to qualify the applicability of the OFETs in simple digital circuits. (c) 2004 Elsevier B.V. All rights reserved.