25Filarial nematodes can cause debilitating diseases in humans. They have complicated 26 life cycles involving an insect vector and mammalian hosts, and they go through a 27 number of developmental molts. While whole genome sequences of parasitic worms are 28 now available, very little is known about transcription factor (TF) binding sites and their 29 cognate transcription factors that play a role in regulating development. To address this 30 gap, we developed a novel motif prediction pipeline, Emotif Alpha, that integrates ten 31 different motif discovery algorithms, multiple statistical tests, and a comparative analysis 32 of conserved elements between the filarial worms Brugia malayi and Onchocerca 33 volvulus, and the free-living nematode Caenorhabditis elegans. We identified stage-34 specific TF binding motifs in B. malayi, with a particular focus on those potentially 35 involved in the L3-L4 molt, a stage important for the establishment of infection in the 36 mammalian host. Using an in vitro molting system, we tested and validated three of 37