An isothermal titration calorimeter was used to measure the excess molar enthalpies (H(E)) of binary systems of 2-octanone or 3-octanone with dodecane, tetradecane, or hexadecane at 298.15 K Under atmospheric pressure. The excess molar enthalpies arc all positive and vary nearly symmetrically with the mole fraction of the ketones. The maximum values Of the excess enthalpies increase with increasing chain length of n-alkanes for the systems containing a given ketone. In addition to a modified Redlich-Kister equation, the Peng-Robinson (PR), the Patel-Teja (PT), and two versions of the Cubic Chain-of-Rotators (CCOR) equations of state were used to correlate the excess molar enthalpies, respectively. The correlated results from the modified Redlich-Kister equation were in good agreement with the experimental values, while the CCOR equation of state with two binary interaction parameters yielded better results than those from other equations of state. The excess molar enthalpy data were also correlated with the NRTL and the Wilson models. It appeared that the NRTL model gave the best representation for those investigated systems.