The whitemouth croaker (Micropogonias furnieri) is one of the most commercially important species along the Atlantic coast of South America. Moreover, some of its biological traits (long life span, inshore feeding, high trophic position) make this species a suitable sentinel of coastal pollution. Here, we investigated contamination by multiple legacy and emerging organic pollutants, such as brominated and chlorinated flame retardants, polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), in whitemouth croakers from two estuaries (Guanabara and Sepetiba Bays) located in industrialized and urbanized areas in Rio de Janeiro State, Southeastern Brazil. Furthermore, we assessed how biological and ecological features could explain the observed contamination patterns. Regarding brominated flame retardants, concentrations of polybrominated diphenyl ethers (PBDEs) varied from 7.6 to 879.7 pg g −1 wet weight (w.w.), with high contribution of tetra-, penta-, hexa-and deca-BDEs. The sum of chlorinated flame retardants (dechlorane-related compounds, ΣDRC) ranged from bLOD to 41.1 pg g −1 w.w., mostly represented by Dechlorane 603 and Dechlorane Plus (DP). Concentrations of PCDDs and PCDFs varied from bLOD to 1.7 pg g −1 w.w., while the Toxic Equivalent