A simple reversed-phase high-performance liquid chromatographic (RP-HPLC) method has been developed and validated for simultaneous analysis of three triterpene acids (corosolic, oleanolic, and ursolic acids) in extracts from inflorescences, leaves, and fruits of Prunus serotina Ehrh. (American black cherry). Separation of the acids was accomplished on a C 18 column (5 µm, 250 mm × 4.6 mm i.d.) and recorded at 210 nm. The greatest resolution was achieved with 90:10 (υ/υ) methanol-1% aqueous orthophosphoric acid as mobile phase at a flow rate of 0.6 mL min -1 . The correlation coefficients for all the calibration plots ( r > 0.998) showed linearity good over the range tested. The relative standard deviation of the method was less than 3.3% for intra and inter-day assays, and average recovery was between 95.9 and 100.9%. Sensitivity was high; detection limits were between 0.034 and 0.067 µg mL -1 . Total amounts of triterpene acids were 0.451-0.928, 0.031, and 0.911-1.455% in the inflorescences, fruits, and leaves of P. serotina , depending on the time of harvesting.