The microstructures of chemically polymerized polypyrrole 100 to 800 Angstrom films were studied by transmission electron microscopy (TEM). The fibers are embedded in an amorphous matrix which forms a self-reinforced composite. The density and size of the fibers were affected by the polymerization time and the concentration ratio of pyrrole and oxidants. The two-dimensional orientation of the crystalline fibers produced strongly anisotropic electrical properties in the thin films. It has been found that by properly adjusting the polymerization condition, it is possible to obtain the polypyrrole conducting ultra thin films with improved mechanic and electric properties.