The leaves and seeds of Telfairia occidentalis are used as vegetables in making soups in Southern Nigeria. In this study, we investigated the antimalarial activity of leaf and seed extracts in vivo in mice infected with Plasmodium berghei berghei during early and established infections. T. occidentalis leaf extract (250-750 mg/kg/day) exhibited antiplasmodial activity both in the 4-day early infection test and in established infection with a marked increase of the mean survival time, which, however, remained lower than that achieved with the standard drug, chloroquine (5 mg/kg/day). The seed extract (450-1,350 mg/kg/day) also demonstrated a promising blood schizontocidal activity in early and established infections. This plant possesses significant antiplasmodial activities, which may be exploited in the control of malaria.