This paper reports new experimental data for the specific enthalpy of the Solution of isobutane (refrigerant R600a, CH(CH(3))(2)-CH(3), CAS Registry No. 75-28-5) with mineral naphthenic compressor oil WF 15A. The experimental data were obtained in the temperature range from (273 to 355) K by a mixing method realized in an ice calorimeter. The behavior of the temperature and weight fraction dependencies of the enthalpy for the refrigerant-oil Solution (ROS) of R600a and mineral compressor oil WF 15A have been examined.