Three extracts (aqueous, methanolic and dichloromethane) of Manihot esculenta (Cassava) leaf were tested in vitro on four development stages of Haemonchus contortus using egg hatch assay (EHA), larval development assay (LDA), L3 migration inhibition assay (LMI) and adult worm motility assay (AWM). Compared to the negative control, significant effects (P < 0.0001) were observed for the methanolic extract of leaf against larval development (57.6% ±7.6), with a dose dependent effect. These results suggest that Cassava possess anthelmintic activity against H. contortus. The active principles responsible for the activity could be the terpenoids and condensed tannin compounds present in the leaf.