Multiple studies about mosquitoes were carried out in several regions in northeastern Algeria, but the region of Guelma was not among them; therefore, the current study came to fill this void. Our inventory offered us a close knowledge of the biodiversity of Culicidae taxa in the region of Guelma that helped us define the presence of 12 species belonging to four genera (Culex, Culiseta, Aedes, and Anopheles). Culex pipiens (52.25%) was the most abundant species known in the north-east of Algeria. As well as Aedes albopictus being second (22.58%), after its new appearance in the region. Notably, results showed the first record of both Anopheles multicolour and Aedes geniculatus in the north-east of Algeria.