We successfully used the guanidine isothiocyanate method for isolation of total RNA from leaf, stem, and root tissues of the aromatic plant Origanum onites. The RNA was extracted with TRI Reagent (R) at room temperature and was recovered by isopropanol precipitation. The isolated RNA was capable of reverse transcription. The extraction method described here does not require ultracentrifugation, and it is fast, simple, and effective. The procedure can be completed within 3 hours and may be applicable to other aromatic medicinal plants containing high amounts of phenolic compounds.