Seasonal and spatial changes in mollusk abundance and composition from sandy bottoms at north platform and gulf of Paria were evaluated during rainy and dry season in 2005. For this, a research hypothesis was formulated: If abundance, richness and/or composition of mollusks in sandy bottoms changes according to seasons and selected localities, then differences in this communities between rainy and dry season, and/or among sampled localities will be found. Two field trips were made on board the Oceanographic Vessel GUAIQUERI II, as part of the environmental baseline study of the Gas Project “Mariscal Sucre” (PDVSA). A multivariate analysis of variance based on permutations (PERMANOVA) was performed, finding only significant differences between rainy and dry season for abundance and species composition (F=5.1438, p<0.05 and F=5.2564, p<0.001, respectively) having a coefficient of variation for season factor of 27% (composition) and 23% (abundance). To sum up, season is the factor which explains the highest variation in abundance and composition of the evaluated mollusk community.