A double-antibody sandwich enzyme-linked immunosorbent assay (ELISA) is described for the detection of Plasmodium falciparum antigen. The test is based on an immunoglobulin (Ig) M capture monoclonal antibody on the solid phase and an IgG monoclonal antibody conjugated to peroxidase. The simple test takes about 2.5 h to complete and, because it uses whole blood with no prior treatment, it is possible to process batches of 50-100 samples simultaneously. The test is specific to P. falciparum and has a sensitivity close to that usually achieved with Giemsa-stained blood films. The reagents employed are stable at refrigerator temperatures for over 6 months, and as the test is compatible with human immunodeficiency virus and hepatitis B surface antigen ELISAs it could be suitable for blood transfusion screening.