Analytical procedures of complex mixtures frequently involve their initial pre-fractionation to make the analysis easier or possible. Recently, SPE is frequently applied for this purpose. This article discusses the possibility of essential oil's fractionation using SPE with octadecyl modified silica. The presented results show that developed SPE with C-18 sorbent allows for easy and total isolation (100% recovery) of low-molecular oxygen compounds from the remaining compounds, for which the recovery exceeds 95%. The obtained recoveries are satisfactory for preliminary separation of essential oils for analytical and preparative purposes.