ABSTRACT. – In order to verify the trophic position and condition of Engraulis anchoita larvae, this study applied stable isotope technique and condition indexes. The area comprises the continental shelf off the Cabo Frio (from 40 to 120 m depth), where a seasonal upwelling of the South Atlantic Central Water (SACW) occurs in summer. Larvae were sampled in winter 2001 and in summer 2002. Stable isotopes of natural carbon (δ^₁₃C) and nitrogen (δ^₁₅N) were measured in larval pools separated by length whereas RNA/DNA, protein and histology were performed for individual larvae. The values of δ^₁₃C for larvae of different developmental phases were similar in winter and summer. Big larvae had a ¹⁵N-enrichment of almost 3‰, in relation to the small ones, showing an increase of trophic level in summer. Despite the variation of RNA/DNA, protein values and histological classification, the tendency of better condition larvae in summer was clear. This variation is related to scenarios of SACW upwelling over the shelf. Those findings agree with the suspended particulate matter and zooplankton isotope values in winter that suggested a more oligotrophic situation than in summer. These results indicate that nutrient enhancement is coupled to better Argentine anchovy larval condition.