Silver nanoparticles were produced by laser ablation of a metal silver plate in an aqueous solution of sodiumdodecyl sulfate, C12H25OSO3Na. The absorption spectrum of the silver nanoparticles is found to be essentiallythe same as that of silver nanoparticles chemically prepared in a solution. The size distribution of thenanoparticles measured by an electron microscope shifts to a smaller size with increase in the concentrationof sodium dodecyl sulfate and with a decrease in the irradiation laser power. These findings are explained bya scheme that the nanoparticles are formed via rapid formation of an embryonic silver particle and a consecutiveslow particle growth in competition with termination of the growth due to SDS coating on the particle.