Located at the north-western tip of Africa, Morocco occupies a particular and unique geographical position as it is the only African country to have two Atlantic and Mediterranean facades participating in its richness in aquatic biodiversity. The importance of this wealth plays a significant role in economic and social development. This work proposes "a study of Bacterial Biodiversity in Atlantic and Mediterranean coastal waters in Morocco" by Physico-chemical, bacteriological methods aiming to analyze the current state of Bacterial Biodiversity in its waters. This study concerned seawater from 15 cities on the Moroccan coast at 18 sites spread over the Atlantic and Mediterranean coasts. The Physico- chemical results show fluctuations during the study period with a maximum peak during the summer season. The bacteriological results have shown the existence of 19 bacterial genus dominated by the vibrion and 86 species indicating a vast bacterial variety participating in the Moroccan marine biodiversity especially near the urban areas of large cities following the diversion excessive wastewater in their coasts without prior treatment and the convergence of the majority of big rivers towards these beaches.

Keywords : Seawater; Biodiversity; Physico-chemical; Bacteriology; Molecular.