The mesostructure of amorphous xerogels based on hydrated zirconia ZrO₂ and its evolution at different stages of heat treatment have been investigated using the small-angle neutron scattering method. A correlation function of the nuclear scattering amplitude density has been obtained from experimental neutron scattering cross sections, and the characteristic radii of ZrO₂ nanoparticles and their specific surface areas have been determined. The influence of the annealing temperature on the fractal properties of the zirconia surface has been elucidated.