In this work we study the structure of Pulsed Laser Deposited silver-containing amorphous carbon a-C:Ag and AlN:Ag composites. The films have the form of a dielectric matrix (a-C or AlN) incorporating metal nanoclusters of 3-10 nm diameters. The composition of the films and the crystal structure of the inclusions have been determined by in-situ Auger Electron Spectroscopy and transmission electron microscopy, respectively. We show that the incorporation of the metal nanoparticles may severely alter the structure and properties of the matrix and a simple rule of mixture does not apply. The interactions of the possible matrix-nanoparticle interfaces were investigated using ab-initio calculations. (C) 2009 Elsevier B.V. All rights reserved.