Polypyrrole-silica nanoparticles were prepd. by in-situ polymn. of pyrrole monomer in the presence of specially modified silica nanoparticles having vinyl functional groups on the surface. The presence of polypyrrole (PPy) on the surface of silica nanoparticles was confirmed using FT-IR spectroscopy. The core-shell morphol. was analyzed by TEM. A uniform and smooth shell of PPy on the silica nanoparticles and absence of free PPy homopolymer were the main features of the proposed method that employs modified silica nanoparticles for the synthesis of the PPy-coated silica nanoparticles. SEM investigation of the particles deposited on a glass surface showed a narrow size distribution with an av. diam. of 240 nm for the particles. The wt. percentage of PPy was estd. using TGA and DSC to be approx. 10 wt.-%. Further investigations a by two-probe cond. method of glass slides coated with the nanoparticles showed an elec. cond. of 7 S • cm-1. The static water contact angle was as high as 169°.