A study has been carried out on sampling methodology to be used in research on the population dynamics of an intertidal community of Scrobicularia plana-Nereis diversicolor, in Bidasoa estuary (SE Bay of Biscay, Spain). Two series of ten samples each were taken out with two different sampling techniques: a 0.1 m² Van Veen grab and 0.1 m² core, and the samples were compared. The minimum volume/area for both abundance and biomass has been calculated for each sampling technique, and for the dominant species: Scrobicularia plana, Nereis diversicolor and Hydrobia ulvae. It is concluded that by using the core method an area of 0.3-0.4 m² is sufficient to represent the structure of the community, whereas by using the grab this area/volume is not reached. The abundance as well as the biomass is greater in the samples taken with the core technique. On the other hand, the standard deviations are greater with the Van Veen grab. Finally, the use of volume instead of area is recommended when using the grab.