The aqueous and chloroform extracts of Acacia nilotica linn belonging to the family Fabaceae were evaluated for anthelmintic activity. The dried powder of Acacia nilotica bark was extracted and the activity was studied. Both aqueous and chloroform extract collected were tested for anthelmintic activity against Indian adult earthworm Pheretima posthuma (Annelida) and recorded the time taken for induction of paralysis and death. Two concentrations (25 mg/ml and 50 mg/ml) of aqueous and chloroform were evaluated in the bioassay involving determination of time of paralysis (P) and time of death (D) of the worms. Piperazine citrate (10 mg/ml) was used as reference standard and normal saline solution as a control. Comparative results of present study indicated that the aqueous and chloroform extracts of leaves of Acacia nilotica, linn shows significantly dose depending pharmacological activity on the earthworms.