The conditions for solid-state synthesis of neodymium yttrium aluminum borate (NYAB) charges have been defined, and crystals with different neodymium concentrations have been grown by spontaneous crystallization from K2Mo3O10-B2O3 fluxes. Decomposition temperatures and lattice parameters of NYAB crystals and synthesized charges have been measured by differential thermal analysis and X-ray diffraction methods. Both (a,c) lattice constants increased with the increasing amount of Nd content, while decomposition temperatures decreased. The distribution coefficient of Nd in NYAB crystals is in the range of 0.6-0.8.