Magnesium salt of 12-tungstophosphoric acid (WPA) hydrate MgHPW12O40-14H(2)O has been investigated in the microwave (X-band) and in the lower frequency (5 Hz-500 kHz) region. The specimens were obtained by pressing powder. Real and imaginary parts of permittivity were obtained for the specimens in both frequency regions. In the microwave region dipolar relaxation was observed with the relaxation time tau = 1.6 X 10(-11) s. This relaxation is attributed to the fast reorientation of H2O molecules. In the lower frequency region ionic jump relaxation was observed with the relaxation time tau = 3.9 X 10(-7) s. Results on ac and dc conductivity are discussed.