Several electrochemical transducers have been developed for use in organic media. These transducers are based on rigid conducting dispersed composites prepared from a mixture of graphite powder in a polymer matrix. The behavior of composites based on silicone, several epoxies, polyester and polyurethane was studied in organic solvents like acetone, acetonitrile, ethanol, chloroform and tetrahydrofuran. The composites were characterized using cyclic voltammetry and were calibrated with ferrocene. Composites with silicone or epoxy showed a high stability in organic solvents. These composites have a homogeneous surface and they show high stability and reproducibility while performing electrochemical measurements. The surface of these devices can be renewed by a simple polishing procedure using alumina paper. The plastic nature of these materials makes them modifiable, permitting the incorporation of fillers before they are cured. To test their capacity for biosensing in organic media, the matrix of one transducer was biologically modified with horseradish peroxidase (HRP) producing a graphite-epoxy-HRP biocomposite. A biosensor built with this material responded linearly to lauroyl peroxide between 10−6 and 10−5 M in acetonitrile and the enzyme remained stable in the biocomposite.