There is a necessity to include sensors (resistors) in the design of organic electronic systems in order to extend the range of possible applications. It is essential to identify potential resistive materials, the processes and methods to structure them and to analyze their resistive properties on flexible substrates. One material widely used in organic electronics is the intrinsically conductive polymer (ICP) poly (3, 4-ethylendioxythiophene) doped with polystyrene sulfonate acid (PEDOT:PSS). In this paper we focus on the DC- and pulsed stress behavior of this conductive polymer on flexible substrates and the resulting changes of his resistive properties.