Anemia is a common condition in HIV-infected children; however, its pathophysiology and the contribution of frequent causes of anemia such as iron deficiency (ID) and malaria are poorly understood. We carried out an ancillary study on the effect of HIV on anemia as part of a case-control study on risk factors of anemia among Mozambican children aged 1-59 months with documented HIV status. Of them, 390 children were admitted to the hospital with anemia (hemoglobin [Hb] < 11 g/dL), whereas 272 children without anemia (Hb ≥ 11 g/dL) were recruited in the community. We assessed differences by HIV status in the presentation of anemia etiological factors and the effect of HIV infection on the association of each factor with anemia. Among the 99 HIV-infected and 563 uninfected children included, HIV-infected anemic children had an increased risk of undernutrition (P < 0.0001), Epstein-Barr virus infection (P < 0.0001), bacteremia (P = 0.0060), a decreased risk of malaria (P < 0.0001), and a similar risk of ID (P = 0.7371) compared with anemic-uninfected children. HIV-infected children were significantly less likely to have anemia associated with Plasmodium falciparum hyperparasitemia (P = 0.0444) and had a lower prevalence of parasitemia in the bone marrow (BM) (P < 0.0001) than anemic-uninfected children. Levels of BM erythropoiesis and dyserythropoiesis were comparable between groups. These findings suggest that the pathophysiology of anemia among HIV-infected malaria-exposed children is not related to HIV-specific effects. For unclear reasons, HIV-infected children had reduced risk of malaria infection, whereas ID prevalence was comparable in HIV-infected and uninfected children, suggesting that iron supplementation recommendations should not be different in HIV-infected children.