The ecosystem-based approach to fisheries management and, more specifically, the European Marine Strategy Framework Directive require the assessment of the state and dynamics of an ecosystem in order to determine suitable management strategies. This paper takes an analytical approach to assess the state of the Bay of Biscay ecosystem in the early 1990s, chosen as a period of reference because key monitoring data series have been collected since then. To assess the state of the ecosystem, the pressures exerted by six broad categories of human activities were examined. A literature review of the ecosystem components was made and a component tree was tailored according to data availability. Data rich components were subdivided into subcomponents for their assessment while data poor components were assessed at an aggregated level. The component tree of the ecosystem comprised six main branches, four of which further divided into sub-components. In total, assessments were carried out at the level of 19 components. For four of these (fished species, sensitive fish species, marine mammals and turtles) the overall assessments were made combining the status of individual species. Impact from human activities were categorised as (i) "widespread" over the whole Bay of Biscay or "local" and (ii) "possible" when they could be logically expected or "documented" when they were reported in the literature. Fishing appeared to be the only activity exerting widespread documented impacts on several ecosystem components. Terrestrial activities had some possible and documented widespread impacts. With the exception of marine transport impacting seabirds at the regional scale through oil pollution, other activities had only local impacts, mostly nearshore. The reference state in the early 1990s, suggests that continuation of monitoring of vertebrates as well as estuarine and coastal habitats must be central to the monitoring programme and management strategies to be set in the context of the Marine Strategy Framework Directive. Additional monitoring is also required for benthos, substrate and micro-organisms.