Mites of family Erythraeidae are parasites in their larval stage and predators in their post-larval stages on a variety of arthropods, among which are important pest species. During 2011-2013, in a faunistic survey of mites associated with beetles of the family Chrysomelidae in Oil and Gas company of Gachsaranregion, Iran. Specimens were preserved in AG (alcohol 75%, glyserin 5%), cleared in lactophenol solution and mounted by Hoyer’s medium. Mite of the genus Leptus (Acari: Erythraeidae) was removed from larva and adult of Cassida persica Spaeth (Coleoptera: Chrysomelidae). The first time in the world C. persica was observed as a new host of Leptus n. sp. It is concluded that Leptus n. sp. can be considered as a valuable addition to the existing IPM methods for Chrysomelid control. Description of new species is in process.