During a therapeutic trial, batches of 672 to 1979 laboratory-bred Aedes polynesiensis, the mosquito vector of lymphatic filariasis in French Polynesia, were fed on Wuchereria bancrofti carriers one, three and six months after they had been treated with either single doses of ivermectin at 100 mcg/kg, diethylcarbamazine (DEC) at 3 and 6 mg/kg or placebo. High mortality rates were observed during the 15-day period following the blood-meal in mosquitoes fed on carriers treated with microfilaricidal drugs and were significantly higher in mosquitoes fed on carriers treated with ivermectin than in those fed on carriers treated with DEC. Though its intensity decreased with the passage of time, the phenomenon was observed in mosquitoes fed on carriers up to six months after treatment, especially in those fed on carriers treated with ivermectin. By decreasing the number of mosquitoes able to transmit the infection, this lethal effect on Ae. polynesiensis might represent an additional advantage of ivermectin in lymphatic filariasis control programs.