The partial molal volumes (φ _v ^° ) and partial molal adiabatic compressibilities (φ _ks ^° ) of glycine and DL-alanine have been obtained in water and aqueous solutions of 0.5, 1.0 and 1.5 mol kg ^-1 sodium sulfate at 288.15, 298.15 and 308.15 K from measurements of density and ultrasonic velocity. Their variations with temperature and their transfer properties from water to aqueous solutions of sodium sulfate have also been obtained. The results have been interpreted in terms of the hydration of the hydrophobic and hydrophilic parts of the amino acids. The φ _v ^° or φ _ks ^° values of the amino acids were regressed to a general equation φ _v ^° or φ _ks ^° =a+bm+cm ² +(T-298.15)(d+em+fm ² ), where m is the concentration of sodium sulfate (01.5 mol kg ^-1 ) and T is the temperature (288.15–308.15 K). The calculated values from the regressed equations are in good agreement with those obtained experimentally with a maximum standard deviation 0.18 cm ³ mol ^-1 for φ _v ^° and 10 ^-4 cm ³ mol ^-1 bar ^-1 for φ _ks ^° .