Objective:To establish diagnostic role of CSF C–reactive protein (CRP) and Adenosine deaminase(ADA) quantitatively in meningitis.Method:This prospective study was done on108 patients. According to serum & CSF analysis 36 cases had pyogenic meningitis, 30 case had tuberculous meningitis and 42 cases had aseptic meningitis. Along with other appropriate investigations,quantitative CSF – CRP and CSF–ADA was assayed and data were analysed to set a diagnostic level and sensitivity and specificity of CSF –CRP and CSF–ADA in meningitis.Result::The differences in the mean values were statistically significant for CSF protein levels, CSF leukocyte count, and CSF/serum glucose between bacterial and aseptic meningitis groups (p<0.001). Values of CSF CRP and CSF ADA had significant difference in different meningitis group (p<0.001).Conclusion:CSF CRP and CSF ADA can easily differentiate bacterial and tuberculous meningitis from other types of meningitis with great sensitivity and specificity .