We compared the tumor necrosis factor (TNF-alpha), interferon gamma (IFN-gamma) and granulocyte-macrophage colony stimulating factor (GM-CSF) serum levels in 87 patients with malaria from the Brazilian Amazon. They included asymptomatic infected individuals and symptomatic patients with mild disease or severe malaria with or without cerebral involvement. As controls we examined individuals living in endemic areas without past history of malaria. The TNF-alpha serum levels were increased in patients with malaria and progressively decreased in those with severe disease 7 days after specific treatment. We found correlation between parasitaemia, TNF-alpha levels and severity of the disease. The correlation between high TNF-alpha levels and severe malaria was independent of cerebral involvement. The increase in both IFN-gamma and GM-CSF levels among malarious patients was not related to the degree of severity or mortality. IFN-gamma concentration, however, was associated with high parasitaemia at admission.