Dielectric permittivity and losses measurements were carried out on crystalline ammonium hydrogen bis-chloroacetate in the frequency range 100-2000 MHz near the transition temperature. The observed dielectric relaxation process was nearly monodispersive. From the analysis of the various experimental results it is suggested that the most probable model of the transition observed in this crystal is the so-called pseudo-spin lattice coupled model given by Nath and co-workers (1979).