In this work, the equilibrium of the system water + 1-butanol + 2-pentanol is studied. Data for isobaric vapor-liquid (VLE) and vapor-liquid-liquid (VLLE) equilibria are obtained at a constant pressure of 101.3 kPa. The equipment used to carry out the experiments is an all-glass dynamic recirculating still, with an ultra-sonic homogenizer coupled to the boiling flask. In addition, liquid-liquid equilibrium (LLE) data at a constant temperature of 303.15 and 313.15 K are analyzed. All the data are found to be thermodynamically consistent and have been correlated by means of different activity coefficients models such as NRTL and UNIQUAC. The results are compared with UNIFAC predictions. (C) 2018 Elsevier Ltd.