The present invention comprises aqueous dispersions comprising a nanoparticulate formulation of crop protection agents in which the nanoparticles have core-shell structures having a mean particle diameter of 0.05 to 2.0 .mu.m and the crop protection agent is present in the core X-ray amorphous together with one or more polymers, where the polymer is not or only partially soluble in water or aqueous solutions or water/solvent mixtures and the shell consists of a stabilizing coating matrix,preparable by a process which comprises (a) preparing a solution of the crop protection agent in a water-immiscible organic solvent, (b) dissolving the core polymer in a water-immiscible organic solvent; and (c) emulsifying the mixture resulting from (a) and (b) with an aqueous solution comprising components of the coating matrix by injecting the corresponding solutions into a mixing chamber and removing the organic solvent after emulsification.