Supercritical antisolvent (SAS) precipitation has been applied to the production of zinc acetate with the aim of evaluating the applicability of this new process to the production of controlled size nanoparticles of catalyst precursors. SAS process is based on the large volumetric expansion of the liquid solvent induced by the fast diffusion of the antisolvent inside the liquid phase. The main process parameter that controlled zinc acetate particle size and particle size distribution (PSD) was the concentration of the liquid solution. Zinc acetate nanoparticles with sizes down to 30 nm and with a mean particle size of 50 nm have been produced. The nanoparticles showed different porosities depending again on the concentration of the liquid solution. BET surface areas up to about 175 m(2)/g were measured using N-2 adsorption.