Hole drift mobility of poly(dibenzofulvene) was found to be 2.7 x 10(-4) cm(2)V(-1) s(-1) at 299 K at a field strength of 7 x 10(5) Vcm(-1) by the time-of-flight (TOF) measurement on a cast film containing 2,4,7-trinitrofluorenylidene-9-malononitrile as an electron acceptor. This value is higher than that of main-chain pi-conjugating poly(pi-phenylenevinylene) (I X 10(-5) cm(2)V(-1)s(-1)), is comparable to that of main-chain sigma-conjugating poly(methylphenylsilane) (I x 10(-4) cm(2)V(-1)s(-1)), and is slightly lower than that of Se (10(-4) cm(2)V(-1)s(-1) order), an inorganic semiconductor.