Foliage part of Hypericum tetrapterum Fries. contains essential oil was collected from north part of Iran. Essential oil was extracted by hydrodistillation method and its components were identified using GC and GC-MS. In this study, thirty-six components (67.21% of total essential oil compositions) were characterized. Alkans (50.07%) and sesquiterpene hydrocarbons (14.42%) were identified as the main fractions of the essential oil together with small amount of monoterpens (0.5 %). The most abundant constituents were n-undecane (30.84%), n-nonane (9.99%), n-tridecane (3.55 %) and β-funebrene (2.79 %).