Vapor-liquid equilibria (VLE) for binary and ternary aqueous solutions of water, monoethanolamine (MEA), N-methyldiethanolamine (MDEA), and 3-(methylamino)propylamine (MAPA) were measured in a modified Swietoslawski ebulliometer at (40, 60, 80, and 100) degrees C. Experimental temperature (T) and total pressure (P) were measured, and the compositions of both the liquid (x) and vapor (y) phases were analyzed. Boiling temperatures (T-b) of pure water and amines were measured over the pressure range of P = (2.5 to 101.3) kPa. Experimental activity coefficients (gamma) were calculated from the experimental P, T, x, and y data and were fit to the Wilson and NRTL equations.