Introduction: To determine the faunal composition of immature culicids inhabiting a percolation tank in the landfi ll of Sapucaia, State of Rio de Janeiro, Brazil, immature mosquitoes were collected over a two-day period during the third weeks of April, August and October 2011. Results: The species found were Culex usquatus, Lutzia bigoti, Anopheles argyritarsis and Limatus durhamii. This study is the fi rst to report the colonization of eutrophic breeding sites by these species. Conclusions: The oviposition behavior observed in this study suggests a secondary adaptation or change in habit to select eutrophic environments during the developmental stages of the observed species.