Abstractobjective Malaria and human immunodeficiency virus (HIV) infection are co-prevalent in subSaharan Africa and cause severe anaemia in children. Interactions between these infections occur in adults, although these are less clear in children. The aim of study was to determine their interaction in a cohort of severely anaemic children.methods Severely anaemic Malawian children were enrolled, tested for HIV and malaria, transfused and followed for 18 months for malaria incidence. Antiretrovirals were not widely available in Malawi during the study period.results Of 381 children (haemoglobin <5 g/dl), 357 consented for HIV testing, 12.6% were HIVinfected, and 59.5% had malaria parasitaemia. At enrolment, HIV-infected children had similar malaria parasitaemia prevalence (59.1% vs. 58.7%; P = 0.96) and parasite density (geometric mean [parasites/ll] 6903 vs. 12417; P = 0.18) as HIV-negative children. There were no differences in mean CD4%, or prevalence of severe immunosuppression, between those with and without malaria parasitaemia. Plasma viral load correlated negatively with log parasitaemia (r = À0.78; P = 0.01). During follow-up, HIV-infected children did not experience more frequent parasitaemias or symptomatic malaria episodes. Adjusted risk estimates (95% CI) for malaria parasitaemia in HIVinfected children at 6 and 18 months follow-up were 0.39 (0.13-1.14) and 0.40 (0.11-1.51), respectively.