The dispersion curves of the dielectric response of NH4HSO4 show that the corrected imaginary part of permittivity, epsilon", and its real part epsilon' versus frequency reveal a dielectric relaxation around 9.1 x 10(5) Hz at 31 degrees C, which shifts to higher frequencies (similar to 10(6) Hz) as the temperatures increases. The relaxation frequency shows an activated relaxation process over the temperature range 31-83 degrees C with activation energy E-a = 0.14 eV, which is close to that derived from the dc conductivity. We suggest that the observed dielectric relaxation could be produced by the H+ jump and SO4- reorientation that cause distortion and change the local lattice polarizability inducing dipoles like HSO4-. (c) 2006 Elsevier B.V. All rights reserved.