In this study, we report the performance of a prototype malaria rapid diagnostic test, Malaria F-test (MFT), compared with thick blood films from HIV-positive Ugandans undergoing malaria testing. In total, 21/154 samples (13.6%) were concordantly positive by both thick film and MFT and 129/154 samples (83.8%) were concordantly negative; 1 sample (0.6%) was thick film-positive but MFT-negative and 3 samples (1.9%) were thick film-negative but MFT-positive. The sensitivity of MFT was 95.5% (95% CI 77.2-99.9%) compared with thick film microscopy and the specificity was 97.7% (95% CI 93.5-99.5%). MFT was simple, rapid and effective for detection of Plasmodium falciparum among HIV-positive subjects in a rural, malaria-endemic African setting.