INTRODUCTION After fourteen years of pioneering systematic work spanning from 1996 to 2010, carried out in the territory of Santa Catarina State, SC, within the Brazilian Southern region, framed in the socalled Atlantic Slope of the Southern Cone of South America (Agudo-Padrón, 2008a), a basic list of continental (land and freshwater) and marine mollusc species was compiled. Besides constant interactions and consultations with numerous national and international specialists, such a list was mostly based on available literature and/or analyses of voucher specimens deposited in collections belonging to research centers or environmental education institutes. To date (up to the first semester of 2010), this list comprises a total of 878 taxa (species and subspecies, including 695 marine and 183 continental forms), and these numbers are likely to increase as field surveys ensue. In the present study, results obtained from the author’s active participation in three recent regional field sampling expeditions dealing with marine and continental mollusc taxa, are reported. I. Official State program for listing and control of invasive exotic species Starting from November 2009, and for the first time in the history of Santa Catarina State, the presence of invasive allochthonous mollusc species in Santa Catarina State was studied and discussed through the organisation of seminars by the Official Foundation for the Environment of the State of Santa Catarina (Fundação do Meio Ambiente – FATMA) jointly with the Hórus Institute for Development and Environmental Conservation (Instituto Hórus de Desenvolvimento e Conservação Ambiental), with the main goal to compile the Official State List of Species. To date, the occurrence of a total of twenty allochthonous (exotic) forms of mollusc species has been confirmed, 14 Gastropoda and 6 Bivalvia namely, 11 terrestrial gastropods, 5 freshwater taxa (3 gastropods and 2 bivalves) and 4 marine bivalves. Taking into account the contributions of Agudo Bleicker (2006a), Agudo-Padrón (2008b) and Agudo-Padrón Lenhard (2010), the slug Pallifera sp. - the taxonomic determination of which is still in process (Thomé et al., 2006) - was included within such a list. Of these twenty Mollusca and environmental conservation in Santa Catarina State (SC, Southern Brazil): current situation