Two spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) is one of the most important and cosmopolitan phytophagous pests with an extensive host plant range e.g. medicinal plants. Up to divers host plant them on some medicinal plants blong to Asteraceae are not study in this areas. In order to this survay, this important and serrius mite were colected (shaking method) from some medicinal plants as host incloding: Feverfew, Holy thistle, Chickory, Prickly lettuce, Safflower, Cotton thistle, Creeping thistle, Yarrow, Echinops plant, Mugwort, Sunflower, Russian knapweed and Greater burdock in Hamedan region during 2009–2010. All specimens on plants were directly mounted on permanent microscopic slides using Hoyer's medium. And also the slides were identified and examined under an Olympus BX51 microscope.
