This study has as objective to identify the species of freshwatermollusks associated with macrophytes Eichhornia azurea, Sagittariamontevidensis e Myriophyllum aquaticum. The site of study located in the Iguariaçá river in the São Borja city, Rio Grande do Sul. The sample areacharacterized by wetland due the flood of the Iguariaçá river. Quantitativesamples were taken in three epochs: august, october and november of 2005.Totalled 731 specimens mollusks, attributed the six species, five gastropods(n = 727) and one bivalve (n = 4). The gastropods species found werePomacea canaliculata (Lamarck, 1822) (n = 4); Gundlachia moricandi(Orbigny, 1837) (n = 263); Lymnaea columella Say, 1817 (n = 88);Stenophysa marmorata Guilding, 1828 (n = 2) and Biomphalaria tenagophila(Orbigny, 1835) (n = 370), and bivalve Eupera klappenbachi Mansur &Veitenheimer, 1975 (n = 4). The mollusks species registered showpreference between the macrophytes and by position in the plant. Themacrophytes could be used as sampling to obtain species restricted at thishabitat, temporarily or permanently, and its presence associated withsubmerged or floating vegetatio
