The concentrations of the chemokines IL-8, monocyte chemotactic protein-1 (MCP-1) and macrophage inflammatory protein-1α (MIP-1α) were measured in 120 CSF samples from 23 patients with pyogenic meningitis and from 11 patients with tuberculous meningitis (TBM) and in 10 CSF from subjects with non-infectious neurological diseases. The chemokine concentrations in patients with meningitis were significantly higher than in control subjects (P < 0·0001). The highest CSF levels were found for IL-8 (median 2917 pg/ml) and MCP-1 (median 2557 pg/ml), whereas those of MIP-1α were less significantly elevated (median 24 pg/ml) (P < 0·0001). Patients with pyogenic meningitis had higher levels of IL-8 and MCP-1 than those with TBM (P < 0·0001). In serial samples from patients with pyogenic meningitis IL-8 levels declined before MCP-1 and MIP-α. In the case of TBM, IL-8, MCP-1 and MIP-1α decreased more gradually during treatment and were detectable in the CSF for several weeks, without any characteristic time course of elimination. These data indicate that patients with pyogenic meningitis and TBM show different chemokine profiles in CSF. The distinct chemokine pattern could be responsible for a differential attraction and activation of leucocytes in the CSF which is reflected in differences in the inflammatory response and clinical course of pyogenic meningitis and TBM.