Silver ion oxidized effectively aniline monomer in the presence of p-phenylene diamine (PDA) promoter in sodium dodecyl sulfate (SDS) micellar medium to polyaniline/silver nanocomposite (PANI/Ag). To compare the results obtained, a sample of PANI polymer lacking Ag nanoparticles was also synthesized by a similar manner using ammonium peroxydisulfate instead of silver ion as the reaction oxidant. The use of PDA promoter/SDS emulsifier system could on one hand decrease the reaction time compared to those of reported previously, and on the other hand, allow the as-reduced silver particles to stay nanosized. The Ag-loaded PANI nanocomposite was structurally confirmed using Fourier transforminfrared and X-ray diffraction techniques. The uniformly dispersed Ag nanospheres with average particle size of 20 nm were clearly detectable in the bright-field micrographs obtained from transmission electron microscopy. Furthermore, thermogravimetric analysis showed that major losses of the mass occurred at two temperature regions including 150–375 ºC and 375–800 ºC.