Common ragweed, Ambrosia artemisiifolia L. (Asterales: Asteraceae), is an annual harmful weed of North American origin, now widely distributed in Central and Southern Europe, Asia and Australia. It is an agricultural weed, but it represents a serious risk for human health because its pollen can cause severe allergies. Recently, in the framework of the EU-COST Action ‘SMARTER’, an European program was started with the aim to develop sustainable management strategies for ragweed in Europe, with a special emphasis in the search and selection of biological control agents. Among them, the record of a new eriophyid mite Aceria species in Serbia has been considered as potential important biological control candidate. This paper describes the species following both morphological and bio-molecular approaches, and is giving some preliminary data on the geographical distribution and on the biology of the eriophyid mite on its host plant.