Densities of and N2O solubilities in aqueous solutions of 1,4-butanediamine (BDA), 2-(diethylamino)-ethanol (DEEA), and their aqueous mixtures were measured at (298.15, 313.15, and 333.15) K, and viscosities were measured at (298.15, 303.15, 313.15, 323.15, and 333.15) K. The experiments cover the mole fraction ranges (1.95-14.3 mol %) BDA, (2.01-19.3 mol %) DEEA, and (3.63-16.7 mol 910) BDA + (2.62-22.2 mol %) DEEA in the blended solutions. The results were compared with available data in the literature. The experimental density and viscosity data were correlated using two semi empirical correlations temperature and concentration of BDA and DEEA. in the literature as functions of