CdS nanoparticles (CdS-nps) were synthesized employing charged and neutral polyamidoamide (PAMAM) dendrimers (generation G3.5, G4.0 and G4.0-OH with 64 -COO-, -NH3+ and -OH peripheral groups, respectively) as templates. The morphological characterization of CdS-nps was carried out using TEM measurements that showed spherical nanoparticles characterized by average diameter values between 3.6 and 4.7 nm. Using UV-vis experiments, CdS-nps formation was evaluated using a diffusion controlled growth model where the S2- diffusion coefficient throughout the external and internal functional groups of dendrimers was found to be an important parameter. In this way, the results indicate that nanoparticle formation is primarily affected by the charged nature of the external functional groups of the dendrimer template. (C) 2012 Elsevier B.V. All rights reserved.