The in vivo antiplasmodial activity of the ethanol leaf extract of Acacia auriculiformis use in the treatment of malaria in Niger Delta region of Nigeria was evaluated in Plasmodium berghei infected mice. The antimalarial activity of the ethanol leaf extract of Acacia auriculiformis (350 ? 1050 mg/kg/day) was evaluated for suppressive activity during early infection in 4-day test and curative activity in established infection (Rane?s test). Acacia auriculiformis (350 ? 1050mg/kg/day)exhibited significant (P<0.05) blood schizonticidal activity both in 4- day early infection test and in established infection with a considerable mean survival time though not comparable to that of the standard drug,chloroquine,5mg/kg/day.The leaf extract possesses significant (P<0.05) antiplasmodial activity which confirms it?s use in folkloric medicine in the treatment of malaria.