Beds of the Atlantic pearl oyster (Pinctada imbricata) and the turkey wing (Arca zebra) of contrasting population densities were evaluated to determine the occurrence of associated decapod crustaceans. In these beds at Cubagua Island, Venezuela, we recorded 40 decapod species belonging to 18 families. Mithraculus forceps (Majidae), Pilumnus caribaeus (Pilumnidae), Cuapetes americanus (Palaemonidae) and Petrolisthes galathinus (Porcellanidae) were the most common species found in these assemblages. The medium- and high-density bivalve beds exhibited more species and a greater abundance of associated decapods than the low-density bivalve beds, and more taxonomic distinctness. Multivariate analysis detected different groups of decapods in the low-density beds and the medium- to high-density beds. Additionally, similarities were found in the communities of crustaceans in the beds of Atlantic pearl oysters and turkey wing, demonstrating that bed density is important for the composition of associated fauna.