Using a volumetric approach, monosaccharides were investigated in terms of temperature and different concentrations. At T = 298.15 K, the densities of D(-)-ribose, D(+)-mannose in H2O and in aqueous saccharin Na salt with molality, m = (0.05, 0.15, and 0.3) mol•kg-1 were determined. The apparent molar volumes (V_), partial molar volumes (V_^0), and Masson's coefficient (S_v) were evaluated by means of experimental density (⍴) values. The data was further analysed in terms of transfer characteristics (∆_trs V_^0), apparent specific volumes (ASV), and volumetric interaction coefficients (V_AB,V_ABB using McMillan–Mayer theory). The significant interactions between the hydrophilic groups of solute (D-ribose and D-mannose) and the Na+ ion of cosolute (saccharin sodium salt) at varied concentrations have been reported. Studied saccharide was found to have a sweet taste in mixed aqueous sodium saccharin.