Densities of aqueous solutions of monoethylethanolamine (MEEA) and diethylethanolamine (DEEA) were measured over the whole range of concentrations at temperatures from 5 to 80 degreesC. Densities of these systems show different behavior at both lower and higher concentration of ethanolamine, This behavior was classified into two zones: at x(2) = 0.12 for (MEEA + water) and at x(2) = 0.04 for (DEEA + water) mixtures. It is found that in the low concentration zone the effect of alkyl groups could be shown as: -CH3 > -C2H5 > 2(-CH3) > 2(-C2H5) The excess molar volumes and excess molar enthalpies of (alkylethanolamine + water) mixtures show similar dependence on the size of the alkyl group present in the alkyethanolamines. The excess molar volumes have the most negative value for the (ethylethanolamine + water) system, while the excess molar enthalpies of the (MEEA + water) system have the more negative value.