We have measured the drift mobility of electrons and holes in thin, vapor‐deposited films oftris(8‐hydroxyquinolinolato‐N1,O8) aluminum using a time of flight photoconductivity technique. The drift of mobility of both carriers is dispersive and strongly electric field and temperature dependent. At ambient temperature and an electric field of 4×105V cm−1, the effective mobility of electrons and holes is 1.4×10−6and 2×10−8 cm2 V−1 s−1, respectively, in a 400 nm thick sample. ©1995 American Institute of Physics.