Plasmodium falciparum, the parasite responsible for potentially fatal malaria, is a major cause of morbidity and of mortality in tropical countries. In vitro culture of Plasmodium remains indispensable for identification of phenotype and surveillance of the efficacy of antimalarial drugs. Culture of Plasmodium falciparum requires the use of RPMI 1640 medium, the efficacy of which depends on addition of human serum. Culture with medium containing either reference human serum of (RS) or serum containing Plasmodium antibodies (SND) provides a plasmodial maturation rate exceeding 20% (lower threshold of validity according to WHO). Comparison of these two culture supplements for in vitro testing of the chemosensitivity of Plasmodium strains to pyrimethamine showed no difference in IC50: < 2000 nM for sensitive strains (FCB1 and PFB) and > 2000 nM for resistant strains (K1).