Cerebrospinal Fluid Adenosine deaminase (ADA) activity and C-reactive protein (CRP) measurement were done in 30 patients of tubercular meningitis (TBM), 36 patients of bacterial meningitis (BM) and 34 patients of Viral meningitis (VM), to evaluate, whether CSF CRP and ADA levels could be used to differentiate the bacterial, tubercular & viral meningitis. The mean CSF ADA activity was significantly raised in TBM as compared to BM and VM. (p< 0.001) while mean CSF CRP activity was significantly raised in BM as compared to TBM and VM. (p< 0.001). At cut of level 10 IU/L, the sensitivity and specificity of ADA for TBM was 90% and 97.14% respectively while at cut of level 15 mg/L, the sensitivity and specificity of the CRP for BM was 86.11% and 98.43% respectively. Since both the tests are simple and take lesser time to perform, they can be used to differentiate BM, TBM and VM.