New potential ytterbium-doped laser crystals-disordered scheelite-like double sodium-gadolinium tungstate NaGd(WO4)2 and sodium-lanthanum molybdate NaLa(MoO4)2, had been grown by Czochralski technique. Polarized absorption and fluorescence spectra as well as fluorescence decay kinetics had been measured for these crystals, doped with Yb3+ ions. Gain cross-section for different population inversion of 2F5/2 level had been calculated.