Au narroparticles were prepared by reduction of HAuCl4 with NaBH4 in the presence of generation 1.5 poly(amidoamine) dendrimers with surface hydroxyl groups (OH-PAMAM-1.5). By optimizing the conditions of the preparation, stable, and uniform Au nanoparticles of 2.7 +/- 0.5 nm were obtained. UV-Vis absorption, Fourier transform infrared (FT-IR) spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM) and electron diffraction (ED) have been used to study the structure and characterization of the nanocomposites. From which, it could be suggested that Au nanoparticles were surrounded by OH-PAMAM-1.5 and the size distribution of Au nanoparticles is narrow. (C) 2003 Elsevier Science B.V. All rights reserved.