For several decades, the bivalve mollusk Anomalocardia brasiliana has been extracted in estuarine areas in the semi-arid region of northeastern Brazil. However, information on both dynamics and abundance of their populations are missing. In this context, the present study, therefore, investigated several aspects of the population structure of A. brasiliana on beaches near the estuary of the Apodi River in Northeast Brazil. The aims were to determine the population density of A. brasiliana during different times of the year, to estimate population parameters, and to relate species density and distribution to the abiotic characteristics of the region. Keywords: bivalve mollusk, growth, recruitment, estuary, tropical. Estrutura populacional do bivalve