A survey of Odonata was carried out in the central region of the state of Rio Grande do Sul: the Taquari River valley. This region was originally covered by deciduous and Semi-deciduous Atlantic Forest, which today only exist in a highly fragmented environment mainly due to agricultural activities. Our survey was conducted in 12 municipalities from this region, between March 2011 and April 2013. Aiming a general overview of the species composition, our sampling sites included lakes, bogs, small streams and river sections, all inside or surrounded by small forest fragments or forest areas. Fifty species of Odonata were collected comprising 29 genera and seven families. The dominant families were Libellulidae (40%) and Coenagrionidae (36%), while Aeshindae, Gomphidae and Lestidae each only comprise 6% of the total number of species. The findings revealed the presence of a highly diverse odonate assemblage, mainly represented by generalist species in human disturbed fragments and a few forest specialist species in the best preserved remnants only.