Electrical and optical properties of the plasma polymerized eucalyptus oil (PPEo) films are discussed in this article. As part of our electrical studies, we have found that the conduction mechanism in the PPEo film is a Schottky type. We have also found that iodine doping can enhance the conductivity of the film. IR studies revealed that PPEo film is a highly crosslinked polymer, and UV-vis-NIR studies revealed the information that optical band gap energy of the PPEo film had been reduced as a result of iodine doping. (C) 2003 Wiley Periodicals, Inc.