Stable Ag nanoparticles of 10-20 nm were prepared by reduction of AgNO3 with NaBH4 in water solution in the presence of low generational hydroxylterminated poly(ester-amine) dendrimer G1.0 (OH)(16) and amino-terminated poly (ester-amine) dendrimer G1.5 (NH2)(8) by optimizing preparation conditions. LJV-vis absorption spectra and transmission electron microscopy were adopted to characterize absorption properties of Ag'/dendrimer complex, Ag/dendrimer nanocomposite aqueous solutions, and the morphology of the formed Ag nanoparticles, respectively. The results showed that the size of the Ag particles increased with Ag+/dendrimer molar ratio, and the size of Ag nanoparticles in Ag/G1.0 (OH)(16) system was larger than that of Ag nanoparticles in Ag/G1.5 (NH2)(8) system, while the polydispersities of two systems were similar. Moreover, the Ag/G1.5 (NH2)(8) nanocomposite system was more stable than the Ag/GI.O (OH)(16) one. (c) 2007 Wiley Periodicals, Inc.