The potential of Artocarpus altilis stem bark as a safe antimalarial agent, and the identification of its antimalarial constituents was explored.The air-dried stem bark was extracted with 70% ethanol, filtered and concentrated in vacuo to obtain the extract (EE). The extract was successively partitioned to give n-hexane (AAH), dichloromethane (AAD), ethyl acetate (AAE) n-butanol (AAB) and aqueous (AAQ) fractions respectively after determining the acute toxicity using Lorke's method. These were each evaluated for chemosuppressive antimalarial activities (0-200mg/kg) against chloroquine-sensitive Plasmodium berghei-berghei-infected albino mice. Normal saline and chloroquine, 10 mg/kg were negative and positive control respectively.The survival times and percentage survivors of the mice in both experiments were determined after observation for twenty-eight days post-drug administration. The five (5) column chromatographic (CC) fractions, AAH1, AAH2, AAH3, AAH4 and AAH5 obtained from the most active AAH, were also evaluated for antimalarial activities (0-50mg/kg). Further column purification and repeated PTLC of AAH5 yielded three bands, which were finally subjected to GC-MS analysis.EE gave ED50 and LD50 values of 227.17and >5000 mg/kg while its partitioned fractions gave ED50 values as follows: AAH, 79.14; AAD, 215.59; AAE, 160.46, AAB, .42; and AAQ, 90.85 mg/kg respectively. The primary CC fractions also gave ED 50 values as follows: AAH1 21.95; AAH2, 26.96; AAH3, 21.30; AAH4, 20.92 and AAH5, 20.75 mg/kg respectively to identify AAH5 as the putative fraction. GC-MS analysis revealed eleven major compounds (1-11) in the three PTLC bands as the antiplasmodial constituents of the plant.The stem bark of A. altilis is a potential agent in malaria control which is safe for oral use.