The mosquito, Culex quinquefasciatus Say, is a vector of Wuchereria bancrofti Cobbold, an etiological agent of Human Lymphatic Filariasis (HLS), which, in its more extreme manifestations is known as elephantiasis. This debilitating disease is still prevalent in many tropics and subtropics, particularly in the Old World tropics. The efficacy of the pyrethroid insecticide Bifenthrin as a potential insecticide for treatment of indoor building walls against Cx. quinquefasciatus was evaluated under laboratory conditions. Six concentrations (0.1, 0.2, 0.3, 0.4, 0.5 and 0.6 percent) of insecticide were sprayed. Knockdown and mortality of mosquitoes were recorded after 5, 15, 30, 60 minutes as well as 6 and 24 hours following exposure. The knockdown effects were positively correlated with the dose and exposure period. The mean percent mortalities for the above mentioned doses after 24 hours of exposure were 11.67%, sx = 0.31; 73.33, sx = 3.33; 80.00, sx = 0.37; 81.67, sx = 0.31; 81.67, sx = 0.31; 83.33, sx = 2.10; 89.00, sx = 2.23, respectively, while the LC50 and LC90 were 0.53 and 1.002 percent respectively. Residual potentiality was tested up to 5 days with the three higher doses where nearly 80% death was recorded at 0.6% concentration after 120 hours of exposure. Bifenthrin 80 SC could be used successfully to control indoor mosquito populations.