Mayotte is an island situated in a region of the world particularly exposed to vector borne diseases. Several potential vectors, a tropical climate, an increasing urbanization, important movements of populations in the region, are among the relevant factors which favour the endemicity, the emergence or the re-emergence of vector transmitted diseases. Many vector born diseases are transmitted by mosquitoes: malaria, dengue, chikungunya, Rift Valley fever and, in the past, the Bancroftian filariosis. A collaborative project was recently initiated between IRD and ARS-OI to update the inventory of the mosquito species present in Mayotte. With the final goal to facilitate an integrated control against vector born diseases transmitted by mosquitoes, an entomological survey was performed in 2011 from March 21st till April 8th, at the end of the rainy season, with special attention in the best-protected natural areas. The breeding sites positive for preimaginal mosquitoes were geolocalised with a GPS and its environment was characterized. A semi-individual breeding of specimens was realized in the insectary from larval and pupal stages. Some mosquitoes were put in collections and the others were put in alcohol to allow further genetic researches by DNA sequencings, in Montpellier. The data concern 27 visited sites, and 426 points of collections. Our provisional results count 26 species (among 36 previously listed). A noticeable result is the discovery of Aedes (Stegomyia) nov. sp., belonging to a new species for Mayotte and for the science, collected in the humid forest at the top of the island (forest reserve of Majimbini) near the locality "The convalescence".