Retention of mono-substituted phenols in reversed-phase liquid chromatography has been studied based on the linear solvation energy relationships using the solvatochromic mobile phase parameters, ${pi}_m^{ast}, {alpha}_m$ and ${eta}_m$. It has been observed that retention behavior of phenols in RPLC were well represented by regression equations vs. solvatochromic mobile phase parameters even though the equations may be incomplete due to lack of an explicit cavity term. Dependence of retention of monosubstituted phenols on the mobile phase properties were varied depending on the type of the organic cosolvent in the mobile phase, e.g., ${eta}_m$ and {alpha}_m$</TEX> in methanol-water system, but ${pi}_m^{ast} and ${eta}_m$ in THF-water system. It has been suggested that retention of phenols in methanol-water system is controlled by the solvophobicity of the mobile phase.