Metals and metal oxide nanoparticles clay supported composites arouse much interest in recent time. In this communication, we report the insitu synthesis of SnO2 nanoparticles by impregnation of SnCl2 center dot 2H(2)O into the nanopores of modified Montmorillonite followed by polyol reduction and aerial oxidation. The modified Montmorillonite having nanopores act as a 'Host' for the SnO2 nanoparticles. The TEM study reveals that SnO2 nanoparticles having size <10 nm are evenly distributed on the support. The XPS results show that the binding energy peaks at 490 and 498.2 eV are due to Sn3d(5/2) and Sn3d(3/2) respectively indicating the presence of Se4+ in the SnO2 nanoparticles. Elemental dot mapping indicate the presence of Al, Si, O and Sn on the surface of AT-Mont. supported SnO2 nanoparticle. The synthesized SnO2 nanoparticles show antibacterial activity against gram +ve and gram -ve bacterial strains. (C) 2016 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.