The efficacy of the Olyset^® net was compared to a net treated conventionally with permethrin 10% emulsifiable concentrate at the World Health Organization recommended dose. The nets were assessed under laboratory conditions against the mosquito vectors Aedes aegypti and Anopheles stephensi. Knockdown efficacy for the Olyset net was assessed after the first 10 washings and then after the 15th and 20th washings. Data were not collected for the conventionally treated netting after 5 washings because the conventional treatment was no longer effective. The results of the study indicate permethrin effectively persisted on Olyset net for at least 20 washings, confirming the regeneration of pesticide after each wash.