In most of sub-Saharan African, drug resistant falciparum malaria has become a major health care concern. Drug sensitivity was evaluated in vivo in Lusaka, Zambia, in 71 episodes in 61 patients with uncomplicated falciparum malaria, for Chloroquin (CQ), Pyrimethamine/sulfadoxine (PS) and halofantrine (HF). CQ resistance was found at R2 (16 pc) and R3 (24.5 pc) level in 37 patients, R3 (10.5 pc) resistance to PS was found among 19 subjects studied. The drug resistance to CQ was inversely related to age.