Interleukin (IL)-1beta is a cytokine released as part of the innate immune response to Plasmodium falciparum. Because the role played by IL-1beta polymorphic variability in conditioning the immunopathogenesis of severe malarial anemia (SMA) remains undefined, relationships between IL-1beta promoter variants (-31C/T and -511A/G), SMA (hemoglobin [Hb] level <6.0 g/dL), and circulating IL-1beta levels were investigated in children with parasitemia (n= 566) from western Kenya.