Insect electrocuting devices using ultraviolet light as an attractant were tested for their ability to reduce mosquito biting in backyards. Biting collections were made in 6 adjacent backyards located in South Bend, Indiana. Two of the yards were equipped with electronic insect killing devices, 2 with CDC traps, and 2 had no apparatus. The collections were made on 8 nights from June through August 1982. The insects killed by the electrocuting devices also were collected. Only 3.3% of the 3212 insects killed on an average night were female mosquitoes. Humans in the vicinity of the electrocuting devices were consistently more attractive to mosquitoes than the devices. Even after 11 days of continuous operation, the electrocuting devices failed to reduce the mosquito biting rate.