Nanophosphors based on yttrium orthoborates doped with Eu3+ or Tb3+ were obtained by the wet chemical synthesis Pechini method with ethylene glycol and citric acid as the reagents promoting copolymerization. Optimal synthesis conditions were found. Crystal structure, morphology and grain size of the nanoproducts were determined on the basis of XRD (X-ray diffraction), EDX (Energy-dispersive X-ray spectroscopy) and TEM (transmission electron microscopy) analysis. Spectroscopic properties were investigated using excitation and emission spectra and luminescence decay curves. Judd-Ofelt intensity parameters were calculated and analysed. The influence of calcination temperature on the physicochemical properties was also examined in order to define the optimum conditions of synthesis.