Electrically conductive cotton, polyester and nylon fabrics have been prepared from conductive polyaniline (PANI) polymer by in situ chemical oxidative polymerization of aniline using ammonium persulphate as the oxidant by a process of diffusion polymerization in a mixed bath. These fabrics are then characterized by ATR-FTIR, WAXD, SEM and DSC. The tensile strength, stiffness and electrical and electromagnetic measurements of the fabric samples are also studied. The structural studies show that the crystalline region of cotton, polyester and nylon is not affected by the polyaniline and the interaction of polyaniline with the fabrics. The SEM studies reveal a very uniform deposition of polyaniline on the fabrics. The thermal studies show that the PANI-treated fabrics have better thermal stability. The intact textile characteristics of the polyester and nylon fabrics coated with PANI are found to be protected, whereas the characteristics of the cotton fabric coated with PANI become inferior. The conductivity studies show that the treated fabrics have good electrical conductivity. The electromagnetic shielding tests show that the cotton, polyester and nylon fabrics have the electromagnetic interference values of -1.62, -2.78 and -1.5 dB respectively in the frequency range 8-12 GHz.