We have fabricated organic field-effect transistors (OFETs) based on three derivatives of perylene tetracarboxylic diimide (PTCDI). The electron mobility more than 8 x 10(-2) cm(2)V(-1)s-(1) has been obtained in both vacuum and air for N,N'-bis(4-fluorobenzyl) perylene-3,4,9,10-tetracarboxylic diimide. The study of the film structures suggests that the flat-layer structures near the SiO2 surfaces induce the high electron mobilities.