The present study has focused on the experimental measurements of the molar heat capacities of four aqueous physical solvents of importance in natural gas sweetening: (1) tetramethylene sulfone (sulfolane), (2) 4-formylmorpholine (NFM), (3) 1-methyl-2-pyrrolidinone (NMP), and (4) triethylene glycol dimethyl ether (TEGDME). The measurements of the molar heat capacities were carried out in the temperature range of (303.15 to 353.15) K and for the entire range of mole fractions. Fractional deviations of the measured molar heat capacities from literature data were less than 1%, and at worst 2%. Molar excess heat capacities were calculated from the measurements and correlated as a function of mole fraction and temperature employing the Redlich-Kister equation. The excess partial molar quantities (C(i)(o) - C(i)(*)) were calculated by extrapolating the reduced excess heat capacity (C(p)(E)/x(1)x(2)) function at x(1) = 0 and x(1) = 1.