Aim: To investigate the phenolic compounds in four Astragalus species (A. hamosus, A. ponticus, A. corniculatus and A. cicer) distributed in Bulgarian flora. Study Design: Using LC-MS, HPLC, UV, NMR and HRESIMS for identification of the compounds. Place and Duration of Study: Department of Pharmacognosy, Faculty of Pharmacy, Medical University of Sofia, Bulgaria, between May 2009 and December 2012. Methodology: LC/MS/MS analysis was performed using Agilent 1100 and API 365 tripequadrupole mass spectrometer. HPLC was carried on a Shimadzu LC–10 Advp chromatographic system included UV-VIS detector SPD. The structure of the flavonoid isolated from A. hamosus was determined by acid hydrolysis, UV, MS and NMR. Results: Seven phenolic compounds were identified in A. ponticus, four in A. corniculatus and three in A. cicer by LC/MS/MS and HPLC. The structure of one flavonoid was established on the basis of UV, NMR and HRMS data as rhamnocitrin-3-Oneohesperidoside. All identified compounds are new for the species and rhamnocitrin-3-O-neohesperidoside – for the genus Astragalus.