This article examines the feasibility of a Ugandan study by James Whitworth and colleagues on the effect of HIV-1 infection and advancing immunosuppression on falciparum parasitemia and clinical malaria. The researchers observed the interaction between malaria and HIV-1 infection in adults with acquired immunity to malaria. Data were collected at the routine quarterly visits and also during interim visits prompted by symptoms. Both clinical malaria and parasitemia were rare. Results showed that HIV-1-positive individuals were more likely to be parasitemic during routine visits than were HIV-1-negative participants and the risk of finding clinical malaria was significantly higher among HIV-1-positive than among HIV-1-negative individuals, whether the visits were routine or interim. These data provide a fascinating insight into the nature of acquired immunity to malaria. Whitworth and colleagues have shown that HIV-1 infection is associated with increased prevalence and intensity of Plasmodium falciparum infection in adults with acquired immunity to malaria. However, this study should include measures of factors influencing HIV transmission and the development of AIDS, as well as variables associated with malaria transmission and response to treatment.