Mosquitoes were surveyed (Oct. 2010 & Apr. - Oct. 2011) in some localities representing 13 centers of El-Dakahlia Governorate. Six mosquito species were collected: Culex pipiens, Cx. antennatus, Cx. perexiguus, Ochlerotatus detritus,
Anopheles pharoensis and An. tenebrosus. Culex pipiens was predominating (ca 79% larvae, 51% adults). Culex antennatus and Cx. perexiguus were also common. Of the Four types of the breeding habitats, the drainage canals were the most productive (53.4% larvae). For the three common species, the compiled larval density increases as water temp. increased and decreases as pH increased while adult indoor density increases as indoor and outdoor temp. and indoor RH increased and decreases as outdoor RH increased. Cx. pipiens significantly associated with Cx. antennatus (CAB=0.88 & I=0.48) while Cx. antennatus has a moderate association with Cx. perexiguus (CAB=0.47 & I=0.36). Out of 908 examined blood samples from ten centers, 7.49% were infected with Wuchereria bancrofti. The highest infection rates in some centers were associated with high indoor densities of Cx. pipiens females, the main filariasis vector. The situation necessitates a wide vector control program to minimize lymphatic filariasis transmission in this Governorate.