Abstract: We studied the dynamic of aquatic snails populations in relation to environmental variables in the Aghien lagoon. Snails and physico- chemical variables were sampled monthly from July 2014 to June 2015 at eleven sampling site. Samplings were performed by the kick sampling technique and Van Veen Grab methods.. A total of 1316 individuals divided into 16 taxa belonging to 4 orders and 10 families were identified. Stations located on the banks were more diversified.