Due to their rich biodiversity, wetlands are of multiple ecological, economic and climatic interest. For the sustainability of these multiple interests and for other functions provided by these types of ecosystems, the assessment of the degree of biodiversity is necessary. Thus, the determination of the specific inventory of systematic taxa is the basis for assessing the degree of quality of this biodiversity. Through this work we have developed a commented inventory of Molluscs from the wetlands of an important plain in Morocco: Gharb. Qualitative surveys of these wetlands have shown that the plain shellfish population is composed of 21 species arranged in 14 genera, 11 families, 3 Orders and two classes. The Gastropods class has 18 species and the Lamellibranch class has only 3 species. In addition, most of the inventoried species are common in other wetlands in Morocco. No species is specific to the plain studied. In addition, the majority of species are holarctic.