Apparent molar heat capacities C-p,C-phi and apparent molar volumes V-phi were determined for aqueous solutions of ethane-1,2-diol, propane- 1,2-diol, and propane- 1,3-diol at temperatures T from 278.15 K to 393.15 K and at the pressure 0.35 MPa. The molalities m investigated ranged from 1.0 mol (.) kg(-1) to about 0.02 mol (.) kg(-1). We used a vibrating tube densimeter (DMA 512P, Anton PAAR, Austria) to determine the densities and volumetric properties. Heat capacities were obtained using a twin fixed-cell, power-compensation, differential-output, temperature-scanning calorimeter (NanoDSC 6100, Calorimetry Sciences Corporation, American Fork, UT, U.S.A.). The results were fit by regression to equations that describe the surfaces (V-phi, T, m) and (C-p,C-phi , T, m). Infinite dilution partial molar volumes V-2(O) and heat capacities C-p(,2)O were obtained over the range of temperatures by extrapolation of these surfaces to m = 0 mol (.) kg(-1).