The macrozoobenthos of Mejillones Bay (23ºS; Humboldt Current), was quan-titatively investigated over a seven years period from austral summer 1995/96 to winter 2002. 78 single van Veen grab samples taken at 6 stations (5, 10, 20m depth) provided the basis for the analysis of the distribution of 60 spe-cies and 28 families as well as their abundance and biomass. Mean abun-dance (2038 ind. m-2) was in the same order compared to a previous investi-gation; mean biomass (2786 g formalin wet mass m-2), however, exceeded prior estimations mainly caused by the dominance of the bivalve Aulacomya ater. 43% of the taxa inhabited the complete depth range. Mean taxonomic Shannon diversity (HŽ, Log e) was 1.54 ± 0.58 with a maximum at 20m (1.95 ± 0.33), evenness increased with depth. The fauna was numerically dominated by carnivorous gastropods, polychaetes and crustaceans (48%), 15% of the species were suspensivorous, 13% sedimentivorous, 11% detritivorous, 7% omnivorous and 6% herbivorous. Cluster analyses showed a significant dif-ference between the shallow and the deeper stations. Gammarids and the polychaete family Nephtyidae characterized the 5-m-zone, the molluscs Aula-comya ater, Mitrella unifasciata and gammarids the intermittent while the gastropod Nassarius gayi and the polychaete family Nereidae were most prominent at the deeper stations. The communities of the three depths did not appear to be limited by hypoxia during non-El Niño conditions. Therefore, no typical change in community structure occurred during El Niño 1997/98, as observed for deeper faunal assemblages and hypoxic bays elsewhere in the coastal Humboldt Current System.