The effects of laser irradiation of silver colloids prepared by laser ablation technique in acetone have been studied. The laser irradiation was performed using laser radiation at different wavelengths (532, 266, 400 and 800 nm). Additional irradiation of colloids resulted in the changes of particles morphology, which were monitored by absorption spectroscopy and transmission electron microscopy methods. The experimental conditions favoring a dimension reduction of the initial particles and a formation of spherical size-controlled nanoparticles were found as well as irradiation conditions aiding the fabrication of nanowires. It was found that both the mean size of the nanoparticles and their stability could be controlled by changing the laser ablation and post-irradiation regimes. (c) 2005 Elsevier B.V. All rights reserved.