Excess molar volumes Vm for (1,3-dimethylimidazolidin-2-one + an alkan-1-of from methanol to octan-1-ol) have been determined from density measurements at T = (283.15, 298.15, and 313.15) K over the whole composition range. The V-m(E) values for the mixtures of 1,3-dimethylimidazolidin-2-one with methanol show the most negative ones at any composition and V-m(E) values for (1,3-dimethylimidazolidin-2-one + an alkan-1-ol) at each temperature varies systematically from negative to positive with an increase in carbon number v in alkan-1-ols. The v dependence of V-m(E)(x1 = 0.5) values for the equimolar mixtures of (1,3-dimethylimidazolidin-2-one + an alkan-1-ol) is very similar to that of (1,1,3,3-tetramethylurea + an alkan-1-ol) at 298.15 K. From the temperature dependence of V-m(E) (x(1) = 0.5) values for the equimolar mixtures of 1,3-dimethylimidazolidin-2-one with an alkan-l-ol, the coefficient partial derivative V-m(E)(x = 0.5)/partial derivative T) P was evaluated for each mixture and its dependence of v was also studied. (C) 2006 Elsevier Ltd. All rights reserved.