By means of potential discharge techniques, hole transport has been investigated in binary solid solutions of triphenylamine and bisphenol‐A‐polycarbonate. Charge was injected from a photoemitting electrode of amorphous selenium. Under space‐charge‐limited conditions, hole transport can be described by a drift mobility that is linearly dependent upon the electric field. For fields of 105V/cm, values of the mobility were between 10−7and 10−5cm2/V s, depending upon the temperature and concentration. The variation with concentration suggests that hole transport occurs by phonon‐assisted hopping between triphenylamine molecules with a charge localization radius of approximately 1.8 A˚.