ultrasound-assisted headspace solid-phase microextraction (ultrasound-assisted headspace solid-phase microextraction) and hydrodistillation (hd) methods, coupled to gas chromatography-mass spectrometry (gc-ms), were used for the extraction and analysis of volatile compounds from hypericum perforatum and hypericum scabrum collected from two different sites in iran. in the ultrasound-assisted headspace solid-phase microextraction method, various experimental parameters such as the type of fiber coating, sonication time, extraction time, extraction temperature and desorption time were investigated. the highest extraction efficiency was achieved by a 100-um polydimethylsiloxane (pdms) fiber. consequently, 36 compounds were identified in h. perforatum and h. scabrum samples, using the ultrasound-assisted headspace solid-phase microextraction-gc-ms method, of which 14 were the same in both species. on the other hand, 57 compounds of these species were identified by the hd-gc-ms method, of which 21 were the same. the predominant constituents identified using the ultrasound-assisted headspace solid-phase microextraction method in h. perforatum included -caryophyllene, -pinene, -cadinene, -selinene, germacrene-d, limonene and myrcene, and in h. scabrum were -pinene, nonane, -pinene and limonene. the common constituents identified by the hd-gc-ms method for h. perforatum involved germacrene-d, limonene, -caryophyllene, -pinene, -pinene and germacrene-b, and for h. scabrum were -pinene, -pinene, germacrene-d, nonane, limonene and -cadinene. the results about the main constituents of the examined species correspond to the findings of other researchers. additionally, comparing ultrasound-assisted headspace solid-phase microextraction-gc-ms and hd-gc-ms methods showed that the ultrasound-assisted headspace solid-phase microextraction-gc-ms method is much faster and simpler, and it requires much less sample size and lower temperature.