Laboratory bioassays were conducted to evaluate the effectiveness of permethrin-impregnated clothing against biting arthropods. Military battle dress uniforms were impregnated at a rate of 0.12-0.15 mg active ingredient (A.I.)/cm2. Gas chromatographic analysis of cloth patches treated showed that over 50% of the chemical remained after 6 cycles of washing. This amount of A.I. (0.06-0.07 mg/cm2) was effective in providing protection against Aedes aegypti and Ixodes ricinus. Mosquitoes and ticks were exposed respectively for 30 sec-3 min and 5-10 min to permethrin-impregnated uniforms: although the knockdown effect diminished with washing, the remaining permethrin provided 100% mortality of the mosquitoes and over 90% mortality of the ticks.