The carrier transport in poly(phenylmethylsilane) films doped with trap‐forming organic compounds with different ionization potentials has been investigated. The carrier transport in the doped systems is discussed as trapping events in the transport‐active host polymer. Zero‐field activation energyE0corresponds well to the ionization potential difference between the additives and host polymer. The field and temperature dependencies of the mobilities have been analyzed in the framework of Gill’s [W. D. Gill, J. Appl. Phys.43, 5033 (1972)] expression. Its characteristic parameterT0, at which the field dependence disappears, has been found to depend on trap depth and concentration, and an explicit expression interrelating them has been experimentally derived.