We describe the benthic macroinvertebrate associations Budi coastal lagoon southern Chile, salt nature. They relate the abundance and biomass species with organic matter levels and types of sediment, 9 stations were chosen for sampling. The muddy bottom is the substrate dominates more than gravel, which is the least represented. Organic matter showed the highest percentages in the mud at stations Allipén and Temo with 87.35 and 84.29% respectively. 8 species were identified, distributed in the Phyla: Annelida (2), Arthropoda (3) and Mollusca (3), being Prionospio patagonica (Polychaeta, Spionidae) and Littoridina cumingi (Mollusca, Cyamiidae) the most abundant species. The highest recorded average abundance per sampling station corresponded to 351 ind. m-2 and the highest average biomass was 1.0132 g m-2 at the station Deume 2. The lowest values of diversity are consistent with the highest values of dominance. ABC curves, indicate that the Budi River, Temo, Allipén, Bolleco, Botapulli, Deume 1 y Deume 3 stations have low disturbance. The results of nonparametric ordination (MDS) indicate that there is a clear segregation into two groups. The main difference between stations is the abundance of the polychaete Spionidae Prionospio patagonica. Different macroinvertebrate communities are closely related to the levels of organic matter and sediment. It states that the macrofauna community comes in two segregations, which are related to coastal features of the lake.