New vapor-liquid equilibrium (VLE) PTx data for two binary mixtures morpholine with 1-butanol and morpholine with 3-methyl-1-butanol under 13 conditions have been measured through a Sweitoslawski-type ebulliometer. Each set of experimental PTx data has been correlated by five activity coefficient models using a Gauss-Newton (GN) optimization procedure, Wilson single parameter, Wilson single-set data treatment, and two versions of the UNIFAC method. Comparisons were also made between available literature values and published data with the present experimental vapor-liquid equilibrium PTx data. The azeotropic points have been determined using the method of Mixon et al.