In this study. the aqueous extract from 90% methanol extract of Myrtus communis L. leaves was analyzed for their phenolic acids content qualitatively and quantitatively using HPLC. Eleven free phenolic acids representing 31.7 % were identified from the aqueous extract of Myrtus communis L. leaves. Elagic, cinnamic and sinapic acids were the most abundant free phenolic acids (19.5 %, 18.6 % and 13.2 %, respectively).  Extensive isolation of the aqueous and ethyl acetate extracts resulted in four known compounds gallic acid (1), Ellagic acid (2), 3,4.3`-tri-O-methyl ellagic acid (3) and 3-O- methylellagic acid 4-0-B-D-glucopyranoside (4). Hypoglycemic activity was confirmed using streptozotocin induced diabetic rats with 400 mg purified aqueous extract of leaves and 100 mg of isolated ellagic acid. These doses were nearly normalized the hyperglycemia within three hours after oral gastric intubations. This study confirmed the Folk medicinal use of Myrtus communis L. leaves as hypoglycemic agent.