The Scleranthus genus, Caryophyllaceae, includes 7 species, which are spread in Bulgaria. Two species S. annuus and S. perennis are used in Bulgarian folk veterinary medicine and in traditional Eastern medicine. The phenolic acids presented in the family Caryophyllaceae might be a useful chemical marker in chemosystematic studies. The composition of the phenolic acids from Scleranthus perennis is analysed for the first time. A method for their purification and isolation by solid phase extraction (SPE) with a good recovery has been developed using Varian (USA) Vac Elut 10 vacuum manifold and reversed phase SPE cartridges C18 (Bond Elut C18, 500 mg, 3 ml). The optimum extraction of the investigated solutes was achieved by acetonitrile-tetrahydrofuran mixture (1:1, v/v) as an eluent. The subsequent high performance liquid chromatography (HPLC) separation was achieved using a reversed phase Spherisorb ODS-2, 5mm (250 x 4.6 mm) column by linear gradient elution mode on a Varian (USA) chromatographic system included UV-VIS detector Model 9050 set at 220, 280 and 310 nm. The mobile phase comprised 20 mM potassium dihydrogen phosphate adjusted to pH 2.98 by phosphoric acid and methanol. The obtained results revealed the presence of derivatives of the protocatechuic, 4-hydroxybenzoic, vanillic, caffeic, syringic, p-coumaric, ferulic, o-coumaric, salicylic and benzoic acids in the studied samples.