Heat capacities of aqueous mixtures of monoethanolamine with 2-amino-2-methyl-1-propanol were measured from 30 degreesC to 80 degreesC with a differential scanning calorimeter (DSC). The heat capacities of 2-amino-2-methyl-1-propanol, 2-amino-2-methyl-1-propanol + water, and monoethanolamine + 2-amino-2-methyl-1-propanol were also studied. Eight binary systems and sixteen ternary systems were studied. The estimated uncertainty of the measured heat capacities is +/-2%. An excess molar heat capacity expression using the Redlich-Kister equation for the composition dependence is used to represent the measured C-p of aqueous alkanolamine solutions. The results (AAD %, the average absolute percentage deviation) for the calculation of the excess molar heat capacities are 3.6% and 13.2% for the binary and ternary systems, respectively. The heat capacities of aqueous mixtures of monoethanolamine with 2-amino-3-methyl-1-propanol presented in this study are, in general, of sufficient accuracy for most engineering design calculations.