A copper catalyzed air oxidation process is presented for polymerization of aniline in a microemulsion constituting with cetyltrimethylammonium chloride (CTAC) and n-butanol. The process was demonstrated to give stable and pitch-dark emulsions of Emeraldine base in molecular weights of 33800 Da, as inferred from the capillary viscometer. A fairly linear viscosity-conversion relation was noted in each case up to 95.0% of conversion. Differential light scattering (DLS) measurements showed 70 nm of average particle size for the polyaniline (PANI) in the emulsion. Conductivities measured by four-point probe technique indicated conductivities 8.3 x 10(-8) and 9.8 Scm(-1) for un-doped and doped PANI.