Successful experimental transmission of the human lymphatic dwelling nocturnal periodic strain of Wuchereria bancrofti has been achieved from man to Indian leaf monkey (Presbytis entellus) through a susceptible strain of Aedes aegypti. The prepatent period varied between 195 and 240 days. Microfilaria (mf) levels were in general low and the peak count was attained at 1800 hr. Of the adult worms 5-12.5% were recovered from male langur while females revealed poor (2.54%) recovery. This host--parasite model thus makes available the target parasite material in substantial quantity to work on chemotherapeutic and immunological investigations.