Precise systematic osmotic coefficient measurements have been carried out for aqueous solutions of different carbohydrates and polyols by using vapor pressure osmometry (VPO) method. Herein, in order to investigate the effect of structure and stereochemistry of solutes on the vapor liquid equilibria behavior of aqueous solutions, we studied the osmotic properties of binary aqueous sugar solutions containing pentose monosaccharides (xylose, ribose and arabinose), hexose monosaccharides (glucose, fructose, galactose and mannose), disaccharides (sucrose, maltose and lactose), trisaccharide (raffinose) and polyols (sorbitol, xylitol and maltitol) at 308.15 K and in the extended concentration range. From the experimental osmotic coefficient data, the values of water activity and vapor pressure of the investigated solutions were obtained. (C) 2016 Published by Elsevier B.V.