Densities, apparent molar volumes, and surface tension of aqueous 3-chloropropan-1-ol and 3-chloropropan-1,2-diol were determined at temperatures from (283.08 to 308.15) K. The results of the volumetric measurements have been used to calculate the following thermodynamic quantities at T = 298.15 K. For 3-chloropropan-1-ol(aq): V-2,m(o) = (79.79 +/- 0.23) cm(3) . mol(-1); (partial derivative V/(o)(2,m)/partial derivative T)(p) = (10.31 +/- 1.28) . 10(-2) cm(3) . K-1 . mol(-1); (partial derivative(2)V(2,m)(o)/partial derivative T-2)(p) = (4.16 +/- 1.46) . 10(-3) cm(3) . K-2 . mol(-1), and for 3-chloroproan 1,2-diol(aq): V-2,m(o) = (80.62 +/- 0.23) cm(3) . mol(-1); (partial derivative V-2,m(o)/partial derivative T)p = (8.499 +/- 1.080) 10(-2) cm(3) . K-1 . mol(-1); (partial derivative(2)V(2,m)(o)/partial derivative T-2)(p) = (1.610 +/-0.67) . 10(-3) cm(3) . K-2 . mol(-1). The preferential interaction parameters of the interaction of 3-chloropropan-1-ol and 3-chloropropan-1,2-diol with two structurally homologous proteins then egg-white lysozyme and alpha-lactalbumin) have been calculated by correlating the measured surface tension data to the surface areas of these proteins. The data on the measured apparent molar volumes and surface tension of aqueous 3-chloropropan-1-ol and 3-chlorupropan-1,2-diol, in combination with the thermal denaturation data and surface area values of hen egg-white lysozyme from literature, clearly indicate a parallel trend in changes in the surface tension of water, partial molar volume, and ability to alter the thermal stability of these proteins.