Laser ablation (LA) of a Ag target in ultrapure water has been performed with nanosecond laser pulses of 355, 532 and 1064 nm in the range of fluences achievable for the particular wavelength. Efficiency of LA process was quantified in terms of the amount of ablated Ag as determined by atomic absorption spectroscopy (AAS) as well as of the area of the surface plasmon extinction (SPE) band of the resulting Ag nanoparticle hydrosol, and a fairly good agreement between the results produced by the two methods was obtained. Sigmoidally shaped plots of the LA efficiency as a function of laser fluence were obtained for LA with all wavelengths of laser pulses examined. Nevertheless, the maximum amount of Ag transferred from the target into the aqueous medium (yielding Ag nanoparticle hydrosol) is substantially (at least 6.5 x) larger for LA performed with 1064 nm pulses than that with 532 nm and 355 nm pulses. On the other hand, polydispersity of the hydrosol ablated with 1064 nm pulses is higher than that of the sols obtained with 532 and 355 nm pulses, most probably due to a limited extent of Ag nanoparticle fragmentation.