La Gouvernance de la Biodiversite Marine et Cotiere dans le Golfe de Guinee.Biodiversity is a holistic concept which encompasses what the scientific literature describes as inter-specific diversity (diversity between species), intra-specific diversity (genetic diversity) and diversity of ecosystems. As a support of life, the preservation of biodiversity in terrestrial and marine habitats is of primary importance for the ecological balance of the Earth. Moreover, it is essential for human beings whose lifestyle depends on nature. The value of biodiversity lies with the opportunities provided to mankind to adapt to a changing environment. Concerning specifically the seas and oceans that constitute ¾ of the planet and 90% of the biosphere, there is a renewed ‘ecological awareness’ at the global level on the need to preserve marine living resources to enable them to continue to generate goods and services for mankind. The urgency to curb the continuous depletion of marine and coastal biodiversity is supported by the facts that the aquatic living resources are not inexhaustible and that damages caused to the marine milieu might be irreversible. Within this broad context, it seemed important to focus on the situation of the coastal States of the Gulf of Guinea for at least two reasons. Firstly, this region is an aquatic biodiversity hotspot whose health is a source of preoccupation not only for the region but for the world at large. Secondly, the region is witnessing an ecological stress with negative outcomes not only on the marine environment but also in the social and economic domains (shortages of sea proteins, loss of revenues derived from fisheries etc.). Thus, the key challenge that lies upon the States of the region is to ensure the optimal preservation of their coastal and marine resources, while exploiting the latter in a sustainable manner in order to drive their national development processes. The analysis of the environmental normative and institutional corpus put in place by those States, both at regional and national levels, shows that the governance framework of marine and coastal biodiversity has still to be adapted to the stakes and challenges it faces. Despite their diversity, the governance mechanisms in the Gulf of Guinea are yet to generate optimal results in terms of ensuring the conservation and sustainable exploitation of living aquatic resources. The declining trend in the loss of marine and coastal species and ecosystems within the region calls therefore for renewed impetus and strategies for an efficient regulation of the Gulf of Guinea’s aquatic patrimony which is so important for the region, and the world at large.