Uniforms impregnated with insect-repelling compounds M-1960, M-2065, and M-2066, after an initial washing, afforded complete protection against the terrestrial leeches Haemadipsa zeylanica and H. picta of North Borneo. After four more washings these compounds still gave protection, although the repellency was not complete. After six washings, the repellent effects of all compounds were not sufficient to be of practical value. No noteworthy differences in repellency of the compounds were noted. Impregnated socks were found to be an effective and feasible method for protecting scantily clad indigenous people against attacks of leeches that attach to the host below the knee.