Poly(o-methoxyaniline) based thin film organic transistors (OTFT's) have been fabricated on a variety of dielectrics: SiO2, polyethylene, and polyvinylidene fluoride trifluoroethylene. Resulting inverted gate OTFT's were found to be P channel with Au contacts. The mobility was measured to be around 10(-3) cm(2) V-1 s(-1) for as-deposited thin film OTFT structures but could be improved by an order of magnitude by doping, annealing, and decreasing the static dielectric constant of the gate dielectric. (c) 2006 American Vacuum Society.