PDMS/gold elastomeric nanocomposites were obtained in a one-pot process based on the use of micelles of a random graft amphiphilic copolymer as reducing nanoreactors for the synthesis of gold nanoparticles within the elastomeric matrix. Optical characteristics of the nanocomposites were very dependent on the composition of the sample, which affected the size and aggregation level of the nanoparticles. Homogeneous dispersions of spherical nanoparticles were obtained for high copolymer/metal solution ratios and low copolymer concentrations. The optical clarity of the materials was retained after polymerization, which is fundamental for optical applications. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)