Cerebrospinal fluid (CSF) samples were collected from 12 patients with pyogenic meningitis (PM), 19 with tuberculous meningitis (TBM), 20 with clinically suspected but not definitely proved cases of tuberculous meningitis (STBM) and 12 normal controls. C-reactive proteins, immunoglobulins G, A, M and mycobacterial antigens were estimated in the CSF samples. Seven out of 51 (13.7%) samples obtained from the patient groups were positive for CRP. Immunoglobulins M and A were significantly raised in the PM group. When the TBM and STBM groups were compared with the controls a highly significant increase was obtained for all immunoglobulins. Mycobacterial antigens/epitopes were identified in 36.8% samples with TBAGB1 and TB68-H monoclonals and in 26.3% with WTB72-A2. In case of patients with suspected TBM, 6.6% were positive with TBAGB1 and WTB72-A2 and 13.3% with TB68-H. However, non-tuberculous patients also reacted with WTB72-A2 (10.5%) and TB68-H (21.0%). This is, to the authors' knowledge, the first report on the presence of CRP in the CSF. Technique for immunoglobulins in CSF is also updated in this paper. We infer that the monoclonal antibody TBAGB1 and immunoglobulins G and A may be safely considered as diagnostic markers of TBM. Estimation of CRP in CSF samples may be made to give a preliminary or additional diagnosis of meningitis regardless of its aetiology.