To avoid overdiagnosis, accuracy in the identification of true malaria cases is of critical importance. Samples (either whole blood, dried blood spots or plasma/serum) collected at the time of clinically diagnosed malaria episodes in a cohort of Malawian HIV-infected mothers and their children were retrospectively tested with the enzyme-linked immunosorbent assay (ELISA) for HRP-2 (histidine-rich protein 2) detection. There were 55 and 56 clinically diagnosed cases of malaria in mothers and children, respectively, with samples available for testing. Rates of laboratory-confirmed episodes were 20% (11 of 55) in mothers and 16.1% (9 of 56) in children. Hemoglobin was lower in children with confirmed malaria compared to those with clinical malaria diagnosis. The results of our study support the widespread use of rapid diagnostic tests.