TBT has been reported as one of the most concerning pollutants, in aquatic coastal systems, (although TBT-based antifouling paints had been banned worldwide in September 2008), since the levels detected in the environment are capable of inducing deleterious effects on the biota. Imposex is characterized by the development of masculine sexual organs in neogastropod females. The deformity 'imposex' is the growth of a penis and/or vas def-erens in female of gastropods. Quantification of TBT by chemical analysis in water or sediment is very onerous, therefore imposex as a tool to detect contamination by organotin compounds is often used. This study reports the first record of imposex observed in gastropod from areas with high shipping activities in Guadeloupe littoral (« Ilet cochon, marina of St francois and riviere sens and harbor of deshais »). We report imposex on 3 species of marine gastropods (Purpula patula, Thais deltoidea, Strombus pugilis). For Purpula patula It has been showed that « deshaies » is more impacted with a 71 % of imposex, then ilet cochon (28%) and saint francois (7%). The marina of « riviere sens » show no imposex. The results of « marina of deshaies » suggesting a higher contamination by the TBT. However, a sensibility different has been observed for those species. On the site « ilet cochon » Strombus pugilis showed 65% of imposex whereas P.patula had 28%. Thus, it is obvious that the present TBT contamination in Guadeloupe influences the multiplication of marine gastropods and could affect the other areas of the Caribbean Sea. Nevertheless, some dosages TBT and a higher sampling should be carry out to complete our conclusions. Further studies will be conducted to assess the use of gasteropod as a bioindicator species. Poster