The binary system studied was monoethanolamine(MEA) + 2-piperidineethanol (2-PE), Heat capacities of aqueous mixtures of MEA with 2-PE were measured from 30 to 80 degreesC with a differential scanning calorimeter (DSC). For mole fractions of water ranging from 0.2 to 0.8, 16 concentrations of the MEA + 2-PE + water systems were studied. An excess molar heat capacity expression, using the Redlich-Kister equation for the composition dependence, is used to represent the measured C-p of alkanolamine aqueous solutions. The results of heat capacity calculation (overall average absolute percentage deviation) for a total of 176 data points for MEA + 2-PE + water system are 0.2 and 7.4% for molar heat capacity and excess molar heat capacity, respectively. The heat capacity values of aqueous mixtures of MEA with 2-PE presented in this study are, in general, of sufficient accuracy for most engineering-design calculations when using MEA + 2-PE + water as absorbent for acid gas removal process.