Contamination by wastewater discharges is one of the main anthropogenic stressor affecting rocky shore assemblages around the world. This study focused on the response of rocky subtidal benthic communities to wastewater treatment plant ( discharges in a very exposed location on the Basque coast (Southeastern Bay of Biscay) To meet the requirements of European Directives Water Framework Directive and Marine Strategy Framework Directive), both benthic macroalgae and macrofauna were considered These both biological elements play a key role in the assessment of the conservation status and functional role of the ecosystem