In this paper studies of the changes of the morphology of silver colloidal nanoparticles under laser irradiation at different fluences and wavelengths have been presented. Silver nanoparticles of size 10-30 nm were prepared in a gelatin stabilized AgNO3 solution under reduction with K-Na-tartrate. They were then exposed to pulsed laser radiation at 532 nm, 400 nm and 266 nm. In addition to the fragmented particles, relatively larger-size (1400-1500 nm) rightangled structures were found to be formed in the solution. The experimental conditions favouring laser-induced transformation of the morphology of nanoparticles have been determined.