In the present study, we describe and analyze the structure of a Late Pleistocene (likely last interglacial) marine macrobenthic assemblage in Caleta Patillos (20°45'S, 70°12'W), northern Chile. A taphonomic analysis suggests the existence of a shallow subtidal paleonvironment, mainly soft-bottom, of high energy and intense mixing from several benthic habitats. The total number of 38 taxa recorded, mainly gastropods and bivalves, was not different than the ones reported in other Late Pleistocene assemblages in northern Chile. At a biogeographic scale, the composition of mo Husk species showed remarkable similarities with present-day fauna, and no extralimital species were recorded. At local scale, however, a comparison with the living assemblage in the same area of study showed a dramatic shift in the species' composition, a result that cannot be explained by sampling bias. A deep and perhaps very recent (i.e., at historical times) alteration of the structure of local macrobenthic assemblages is hypothesized