The main objective of this study is to measure the heat of absorption of CO2 in two promising aqueous amine solutions at different operating conditions. The heat of absorption of CO2 in aqueous 3-(Dimethylamino)-1-propylamine (DMAPA) and 1-Methylpiperazine (1MPZ) were measured using a flow calorimeter at (313.15 and 343.15) K and at (1, 2 and 2.6) MPa. Measurements were performed at two concentrations of aqueous amine solutions (15 and 30) wt. %. A mixing flow CELL was integrated inside a C-80 heat calorimeter was manufactured for us by Setaram (Caluire, France). Aqueous amine and CO2 were transferred to the mixing flow cell at pre-determined flow-rates in order to measure the heat of absorption at given temperatures and pressures. Different flow-rates of aqueous amine solutions and CO2 were used to reach different CO2 loadings (mole of CO2/ mole of amine). The heat of absorptions per mole of CO2 at infinite dilution for aqueous solutions of DMAPA and 1MPZ were estimated from the experimental heat of absorption data. Heats of absorption for 1-MPZ were much lower than those of Monoethanolamine (MEA) at all concentrations. Values for aqueous DMAPA solutions were identical to those for MEA.