Host preferences of mosquitoes, mainly Culex pipiens L. and Aedes caspius (Pallas), were studied in Israel using live baits, chemical attractants, light, and suction traps. The feeding habits of Cx. pipiens were opportunistic. This species used a wide range of mammalian and avian hosts; a calf, chickens, turkeys, and sheep were the most attractive baits. A. caspius fed mainly on large mammals and was most attracted to calf and sheep baits. Although sheep were attractive, few Cx. pipiens and no Ae. caspius engorged after entering the traps. In addition to defensive behavior and the mechanical protection afforded by the wool, sheep may possess a close-acting repellent that deters mosquitoes from biting. CO2 was the best attractant for host-seeking Cx. pipiens and Ae. caspius, Aedes detritus (Haliday), Culiseta annulata (Schrank), Culiseta longiareolata (Macquart), and Uranotaenia unguiculata Edwards were caught in small numbers, and their bloodmeal hosts were recorded.