Isothermal vapor-liquid equilibria (VLE) data and mixture critical points data were measured for the n-pentane + 1-butanol and n-pentane + 2-butanol systems at 468.15 K, 483.15 K, 498.15 K, and 513.15 K. A circulation-type apparatus with a view cell was used, and critical pressures were determined from the critical opalescence of the mixtures. These mixtures show non-ideal behavior because of the hydrogen bonding of the alkanol. The measured data were correlated with the Peng-Robinson-Stryjek-Vera equation of state (EOS) with the Wong-Sandler mixing rule and the statistical associated fluid theory. Both the EOS failed to correlate the experimental data near the critical region.