Southern house mosquitoes (Culex quinquefasciatus Say) breed in a wide variety of conditions, including water polluted with organic and inorganic substances. This study investigates the effects of two inorganic pollutants on three larval control methods. Hexavalent chromium pollution has been shown to decrease survival and delay larval development of C. quinquefasciatus at ecologically relevant levels. Very high levels of perchlorate, such as those found only at the most polluted industrial sites, have also been shown to increase mortality and delay development. We tested the effects of these pollutants on three widely used mosquito control methods, including two microbial controls, Bacillus thuringiensis var israelensis (Bti) and Bacillus sphaericus, and methoprene, an insect growth regulator. Tests for efficacy of Bti and B. sphaericus were performed with 4th instar larvae, and mortality was assessed after 24 hours. Tests for efficacy of methoprene were begun with 4th instar larvae, and mortality was assessed daily until all insects had died or emerged. The presence of hexavalent chromium or perchlorate increases the efficacy of Bti and B. sphaericus. Implications for use of mosquito control materials at contaminated sites will be discussed.