The macrofauna from a shallow (12 m), sandy bottom at Bredholmen in the outer Lysekil archipelago, western Sweden, was collected quantitatively with a suction sampler at regular intervals between June 1980 and August 1981. This area was inhabited by a dense population of the burrowing crustacean Upogebia deltaura, with a rich infaunal community, high in abundance and diversity throughout the study period. A total of 7297 individuals comprising 126 taxa were obtained from the 52 samples (four replicates on each occasion). A total of 64 polychaete taxa were found, followed by 22 molluscs, 21 crustaceans, 7 echinoderms, and 12 species not belonging to any of these taxonomical groups (varia). Molluscs dominated in abundance throughout the study period except , when polychaetes dominated. Species abundance varied seasonally. The multivariate analyses of abundance data also demonstrated a limited temporal change, less pronounced during winter months. Bottom water salinity was negatively correlated to the number of taxa. Bottom water temperature was negatively correlated to polychaete abundance, and positively correlated to mollusc abundance. Upogebia deltaura correlated positively with four taxa: Nereimyra sp., Spisula subtruncata, one species within the family Talitridae, and Mya truncata, and negatively to Scoloplos armiger.