The first (K1) and second (K2) acidic dissociation constants of glutaric acid in11.52% by weight 1,3-dimethyl urea in water have been determined from e.m.f. measurements of cells without transference. The lowest K1 and K2 values, over the experimental temperature from 278.15 to 318.15 K, were those obtained at 298.15 K. The value of K1/K2 in the present work was ~27 as compared with ~12 in water. The results have also been used to calculate the standard changes of enthalpy, entropy and heat capacity for the two dissociation processes in the aqueous dimethyl urea. The evidence indicates relatively greater acid-anion stabilization as compared with water.