Malaria is an important mosquito-borne disease in Tihama lowland areas of Saudi Arabia and the health authority is currently, adopting a national policy for malaria elimination. Due to scarcity of information on the ecology of larval population of mosquito vectors in this area, the present study was conducted in an attempt to provide updated knowledge on this aspect in the study area. The study was conducted in 3 ecologically different strata known as malaria endemic in Tihama lowland. The larval ecology was studied over a 24-month period and a total of 7712 mosquito larvae were collected between October 2005 and September 2007. The larval fauna composed of 7, 11 and 4 species of the genera Anopheles, Culex and Aedes, respectively. The study encountered Cx. duttoni, Cx. decens and Cx. bitaeniorhynchus, as first record in Saudi Arabia. Six types of habitats were surveyed, the most significant of which was wadi (valley)habitat. Anopheles arabiensis showed significant tendency towards breeding in wadi habitat, whereas An. sergentii breed readily in at least 3 different habitats. Depth and temperature of water are significant characters in the occurrence and density of An. arabiensis.