The influence of oceanographic fronts on the abundance and community composition of invertebrate larvae, mostly of benthic species, along nearly 2000 km of the southwestern Atlantic shelf (21–34°S) was investigated. Meroplankton was sampled through vertical hauls at 89 stations, distributed along 14 cross-shelf transects, during late spring 2010 and early summer 2011. Salinity and temperature were registered with a CTD/rosette system, which provided seawater for chlorophyll-a and nutrient concentrations estimations. Vertical profiles of temperature, salinity, chlorophyll-a and nutrients were used as proxies of the fronts. In addition, high-resolution thermosalinograph data were used to detect surface frontal features. Meroplankton abundance peaks were found at several fronts intersected by the ship, including upwelling zones, estuarine and plume fronts, a shelf-break front, and two cyclonic eddies. Furthermore, meroplankton abundance was also relatively higher at small-scale thermal and/or saline surface fronts observed along the shelf. Such increases in meroplankton abundance are likely to be ascribed to high nutrient input and primary production. Distinct taxa of invertebrate larvae occurred at different types of fronts, besides the coastal realm, which was virtually dominated by decapod, cirripede and bivalve larvae. Small-scale shelf fronts presented high abundances of decapod and gastropod larvae, for instance, while larvae of polychaetes were the most frequent in the estuarine front of Patos Lagoon section.