The density (�), viscosity (η), surface tension (�), and refractive index (nD) of aqueous solutions of piperazine and aqueous blends of 2-amino-2-methyl-1-propanol (AMP) with piperazine were experimentally measured for a wide range of temperature (298.15 to 333.15) K. The physical properties were measured for piperazine mass fractions (1.74, 3.45, 6.88, and 10.35) and for aqueous blends of (AMP + PZ) with mass fractions 100 (w 1/w2) = (28.26/1.74), (26.55/3.45), (23.12/6.88), (19.65/10.35). The concentrations for aqueous solutions of (AMP + PZ) were kept higher due to the growing interest in use of concentrated amines in gas processing. All of the measured physical property values were correlated as a function of temperature. © 2011 American Chemical Society.