Electrically conductive polythiophene (PT) films were first deposited onto p-type silicon by using electrochemical techniques. The deposition of PT were detected by cyclic voltammetry, surface reflection i.r. spectroscopy and scanning electron microscopy (SEM) images. The morphology and conductivity of the PT films deposited on monocrystalline silicon (MS) were much different to those of the films deposited on porous silicon (PS).