Knowledge of low vapor pressures p(0) is indispensible for modeling the fate of chemicals in the environment as well as for other important applications. The indirect determination of vapor pressures by the capillary gas-liquid chromatography-relative retention time (GLC-RT) technique has attracted the attention of many research groups, and two review papers devoted to this topic have already been published. To complement these reviews, the quality of the literature vapor pressures for reference compounds is analyzed, along with the influence of the equations used for the temperature dependence of p(0) and the effects of the extrapolation interval applied. Since the GLC-RT techniques yield p(0) of subcooled liquid even in the case of solid samples, different approaches employed for the recalculation of solid vapor pressures for reference compounds to the values for subcooled liquids are discussed. It is shown that a selection and/or application of the physicochemical properties of the reference compounds can significantly influence the quality of the GLC-RT based vapor pressures and, if improperly selected/applied, even lead to vague and physico-chemically groundless results. In an effort to allow potential users to make an informed decision about what reference data and/or methodology to use to improve the reliability of the GLC-RT based vapor-pressure data, we present a set of recommendations and advisories for appropriate reference data use and manipulation.